diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..748e64a
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,12 @@
+# Compiled
+*.class
+target/
+
+# IDE
+.idea/
+*.iml
+.vscode/
+
+# OS
+.DS_Store
+Thumbs.db
diff --git a/README.md b/README.md
index e69de29..640afa8 100644
--- a/README.md
+++ b/README.md
@@ -0,0 +1,127 @@
+# 🧙‍♂️ Workshop: Hogwarts School System - A Magical OOP Adventure
+
+## Welcome, Young Wizard!
+
+> *"The sorting hat has placed you in Gryffindor... No, wait! It placed you in the **Java Development** house!"*
+
+Welcome to the **Hogwarts School System** workshop! This magical journey will help you master the fundamentals of **Object-Oriented Programming (OOP)** through a fun, wizard-themed project.
+
+---
+
+## 🎯 Workshop Objectives
+
+By completing this workshop, you will learn and practice:
+
+| Concept | How it's used in this project |
+|---------|-------------------------------|
+| **Encapsulation** | Private fields with public getters/setters |
+| **Inheritance** | `Student` and `Teacher` extend `User` |
+| **Polymorphism** | Different user types with same methods |
+| **Abstraction** | Abstract `User` class with common behavior |
+| **Lists & Collections** | Managing students, teachers, and courses with `ArrayList` |
+| **Input Validation** | Validating usernames and passwords |
+| **ID-based Selection** | Finding courses by unique ID instead of name |
+
+---
+
+## 🏰 Storyline
+
+*Professor Dumbledore has asked you to help modernize Hogwarts! The old parchment-based course enrollment system is a disaster. Students keep signing up for the wrong classes, and Professor Snape is furious because his Potions class is full of first-year students who can't tell a bezoar from a newt's eye.*
+
+*Your mission: Build a digital School Management System that allows:*
+
+- *Students to view available courses and enroll using magical Course IDs*
+- *Teachers to create new courses and manage their classes*
+- *Everyone to log in securely (even Filch needs to check who's where)*
+
+---
+
+## 📚 Class Hierarchy Diagram
+```plaintext    
+
+        ┌─────────────────┐
+        │ User            │
+        │ (Abstract)      │
+        └────────┬────────┘
+                 │
+  ┌──────────────┴──────────────┐
+  │                             │
+┌─────▼─────┐             ┌─────▼─────┐
+│ Student   │             │   Teacher │
+└─────┬─────┘             └─────┬─────┘
+      │                         │
+┌─────▼─────┐             ┌─────▼─────┐
+│enrolled   │             │ myCourses │
+│ Courses   │             │   (List)  │
+└───────────┘             └───────────┘
+
+┌─────────────────┐
+│ Course          │
+├─────────────────┤
+│ - id (static)   │
+│ - name          │
+│ - teacher       │     
+│ - students      │
+└─────────────────┘
+       │
+       │ contains
+       ▼
+┌─────────────────┐
+│ SchoolSystem    │
+│ (Service)       │
+└─────────────────┘
+
+```
+
+
+
+
+
+---
+
+## 📋 Complete TODO List
+
+### 🔧 Student.java (3 TODOs)
+
+| # | Method | Description |
+|---|--------|-------------|
+| 1 | `enrollInCourse(Course course)` | Register student in a course |
+| 2 | `showMyCourses()` | Display all enrolled courses |
+| 3 | `getEnrolledCourses()` | Return list of enrolled courses |
+
+### 🔧 SchoolSystem.java (5 TODOs)
+
+| # | Method | Description |
+|---|--------|-------------|
+| 4 | `registerStudent(String username, String password)` | Register new student |
+| 5 | `loginStudent(String username, String password)` | Student login |
+| 6 | `findStudent(String username)` | Find student by username (private) |
+| 7 | `addCourseToSystem(String courseName)` | Add new course to system |
+| 8 | `findCourseById(int id)` | Find course by ID |
+
+### 🔧 Main.java (4 TODOs)
+
+| # | Location | Description |
+|---|----------|-------------|
+| 9 | `registerMenu()` - case 1 | Student registration |
+| 10 | `loginMenu()` - case 1 | Student login |
+| 11 | `studentMenu()` - case 3 | Show my courses |
+| 12 | `enrollInCourse(Student student)` | Enroll logic |
+
+### 📊 Summary
+
+| File | TODO Count |
+|------|------------|
+| Student.java | 3 |
+| SchoolSystem.java | 5 |
+| Main.java | 4 |
+| **Total** | **12** |
+
+---
+
+## ℹ️ Note
+
+> This exercise is for practice only and has no bouns.  
+> Students can complete it in class with TA assistance.
+
+**Good luck, young wizard!** ✨
\ No newline at end of file
diff --git a/pom.xml b/pom.xml
new file mode 100644
index 0000000..8fe5d97
--- /dev/null
+++ b/pom.xml
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
+         http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>org.example</groupId>
+    <artifactId>WS-04-oop-review</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>14</source>
+                    <target>14</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+</project>
diff --git a/src/main/java/Main.java b/src/main/java/Main.java
new file mode 100644
index 0000000..edfa2f5
--- /dev/null
+++ b/src/main/java/Main.java
@@ -0,0 +1,283 @@
+import models.*;
+import services.*;
+import java.util.Scanner;
+
+public class Main {
+    private static SchoolSystem school = new SchoolSystem();
+    private static Scanner scanner = new Scanner(System.in);
+
+    public static void main(String[] args) {
+        school.addCourseToSystem("Potions");
+        school.addCourseToSystem("Defense Against Dark Arts");
+        school.addCourseToSystem("Transfiguration");
+
+        runMainMenu();
+    }
+
+    private static void runMainMenu() {
+        while (true) {
+            System.out.println("\n    HOGWARTS SCHOOL SYSTEM ");
+            System.out.println("1.  Register (Sign Up)");
+            System.out.println("2.  Login");
+            System.out.println("3.  Exit");
+            System.out.print("\nChoose: ");
+
+            int choice = getIntInput();
+
+            switch (choice) {
+                case 1:
+                    registerMenu();
+                    break;
+                case 2:
+                    loginMenu();
+                    break;
+                case 3:
+                    System.out.println(" Goodbye!");
+                    return;
+                default:
+                    System.out.println(" Invalid choice!");
+            }
+        }
+    }
+
+    private static void registerMenu() {
+        System.out.println("\n══════════ REGISTER ══════════");
+        System.out.println("1.  Register as Student");
+        System.out.println("2.  Register as Teacher");
+        System.out.println("3.  Back");
+        System.out.print("Choose: ");
+
+        int choice = getIntInput();
+
+        System.out.print("Enter username: ");
+        String username = scanner.nextLine();
+
+        String usernameError = User.validateUsername(username);
+        if (usernameError != null) {
+            System.out.println(" " + usernameError);
+            return;
+        }
+
+        System.out.print("Enter password: ");
+        String password = scanner.nextLine();
+
+        String passwordError = User.validatePassword(password);
+        if (passwordError != null) {
+            System.out.println(" " + passwordError);
+            return;
+        }
+
+        boolean success;
+        switch (choice) {
+            case 1:
+                //TODO
+                break;
+            case 2:
+                success = school.registerTeacher(username, password);
+                if (success) {
+                    System.out.println(" Teacher registered successfully!");
+                } else {
+                    System.out.println(" Username already exists!");
+                }
+                break;
+            case 3:
+                return;
+            default:
+                System.out.println(" Invalid choice!");
+        }
+    }
+
+    private static void loginMenu() {
+        System.out.println("\n══════════ LOGIN ══════════");
+        System.out.println("1.  Login as Student");
+        System.out.println("2.  Login as Teacher");
+        System.out.println("3.  Back");
+        System.out.print("Choose: ");
+
+        int choice = getIntInput();
+
+        System.out.print("Username: ");
+        String username = scanner.nextLine();
+        System.out.print("Password: ");
+        String password = scanner.nextLine();
+
+        switch (choice) {
+            case 1:
+                //TODO
+                break;
+            case 2:
+                Teacher teacher = school.loginTeacher(username, password);
+                if (teacher != null) {
+                    teacherMenu(teacher);
+                } else {
+                    System.out.println(" Invalid username or password!");
+                }
+                break;
+            case 3:
+                return;
+            default:
+                System.out.println(" Invalid choice!");
+        }
+    }
+
+    // ==================== STUDENT MENU ====================
+    private static void studentMenu(Student student) {
+        while (true) {
+            System.out.println("\n══════════ STUDENT DASHBOARD ══════════");
+            System.out.println("Welcome, " + student.getUsername() + "!");
+            System.out.println("1.  View All Available Courses");
+            System.out.println("2.  Enroll in a Course");
+            System.out.println("3.  View My Courses");
+            System.out.println("4.  Logout");
+            System.out.print("\nChoose: ");
+
+            int choice = getIntInput();
+
+            switch (choice) {
+                case 1:
+                    System.out.print(school.getAllCoursesDisplay());
+                    break;
+                case 2:
+                    enrollInCourse(student);
+                    break;
+                case 3:
+                    //System.out.print(student.getMyCoursesDisplay());
+                    break;
+                case 4:
+                    System.out.println(" Goodbye, " + student.getUsername() + "!");
+                    return;
+                default:
+                    System.out.println(" Invalid choice!");
+            }
+        }
+    }
+
+    private static void enrollInCourse(Student student) {
+       //TODO
+    }
+
+    // ==================== TEACHER MENU ====================
+    private static void teacherMenu(Teacher teacher) {
+        while (true) {
+            System.out.println("\n══════════ TEACHER DASHBOARD ══════════");
+            System.out.println("Welcome, Professor " + teacher.getUsername() + "!");
+            System.out.println("1.  View All Available Courses");
+            System.out.println("2.  Add New Course to System");
+            System.out.println("3.  View My Courses");
+            System.out.println("4.  Add Course to My List (by ID)");
+            System.out.println("5.  Remove Course from My List (by ID)");
+            System.out.println("6.  View Students in My Course (by ID)");
+            System.out.println("7.  Logout");
+            System.out.print("\nChoose: ");
+
+            int choice = getIntInput();
+
+            switch (choice) {
+                case 1:
+                    System.out.print(school.getAllCoursesDisplay());
+                    break;
+                case 2:
+                    addNewCourseToSystem(teacher);
+                    break;
+                case 3:
+                    System.out.print(teacher.getMyCoursesDisplay());
+                    break;
+                case 4:
+                    addCourseToTeacher(teacher);
+                    break;
+                case 5:
+                    removeCourseFromTeacher(teacher);
+                    break;
+                case 6:
+                    showStudentsInTeacherCourse(teacher);
+                    break;
+                case 7:
+                    System.out.println(" Goodbye, Professor " + teacher.getUsername() + "!");
+                    return;
+                default:
+                    System.out.println(" Invalid choice!");
+            }
+        }
+    }
+
+    private static void addNewCourseToSystem(Teacher teacher) {
+        System.out.print("Enter new course name: ");
+        String courseName = scanner.nextLine();
+
+        if (school.addCourseToSystem(courseName)) {
+            System.out.println(" Course '" + courseName + "' created successfully!");
+            Course newCourse = school.findCourseByName(courseName);
+            if (newCourse != null) {
+                teacher.addCourse(newCourse);
+            }
+        } else {
+            System.out.println(" Course already exists!");
+        }
+    }
+
+    private static void addCourseToTeacher(Teacher teacher) {
+        System.out.print(school.getAllCoursesDisplay());
+        System.out.print("\nEnter Course ID to add to your list: ");
+        int courseId = getIntInput();
+
+        Course course = school.findCourseById(courseId);
+        if (course == null) {
+            System.out.println(" Course not found!");
+            return;
+        }
+
+        if (teacher.addCourse(course)) {
+            System.out.println(" Course '" + course.getName() + "' added to your list!");
+        } else {
+            System.out.println(" You already teach this course!");
+        }
+    }
+
+    private static void removeCourseFromTeacher(Teacher teacher) {
+        System.out.print(teacher.getMyCoursesDisplay());
+        if (teacher.getMyCourses().isEmpty()) return;
+
+        System.out.print("\nEnter Course ID to remove from your list: ");
+        int courseId = getIntInput();
+
+        Course course = school.findCourseById(courseId);
+        if (course == null) {
+            System.out.println(" Course not found!");
+            return;
+        }
+
+        if (teacher.removeCourse(course)) {
+            System.out.println(" Course '" + course.getName() + "' removed from your list!");
+        } else {
+            System.out.println(" You don't teach this course!");
+        }
+    }
+
+    private static void showStudentsInTeacherCourse(Teacher teacher) {
+        System.out.print(teacher.getMyCoursesDisplay());
+        if (teacher.getMyCourses().isEmpty()) return;
+
+        System.out.print("\nEnter Course ID to see students: ");
+        int courseId = getIntInput();
+
+        Course course = school.findCourseById(courseId);
+        if (course == null) {
+            System.out.println(" Course not found!");
+            return;
+        }
+
+        String result = teacher.getStudentsDisplayForCourse(course);
+        System.out.println(result);
+    }
+
+    private static int getIntInput() {
+        try {
+            int value = scanner.nextInt();
+            scanner.nextLine();
+            return value;
+        } catch (Exception e) {
+            scanner.nextLine();
+            return -1;
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/models/Course.java b/src/main/java/models/Course.java
new file mode 100644
index 0000000..2901c3b
--- /dev/null
+++ b/src/main/java/models/Course.java
@@ -0,0 +1,68 @@
+package models;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Course {
+    private static int nextId = 1;
+
+    private int id;
+    private String name;
+    private Teacher teacher;
+    private List<Student> students;
+
+    public Course(String name) {
+        this.id = nextId++;
+        this.name = name;
+        this.students = new ArrayList<>();
+    }
+
+    public int getId() { return id; }
+    public String getName() { return name; }
+    public Teacher getTeacher() { return teacher; }
+
+    public void setTeacher(Teacher teacher) {
+        this.teacher = teacher;
+    }
+
+    public boolean addStudent(Student student) {
+        if (students.contains(student)) {
+            return false;
+        }
+        students.add(student);
+        return true;
+    }
+
+    public List<Student> getStudents() {
+        return students;
+    }
+
+    public String getStudentsDisplay() {
+        if (students.isEmpty()) {
+            return "  No students enrolled yet.";
+        } else {
+            StringBuilder sb = new StringBuilder("  Students in " + name + ":\n");
+            for (Student s : students) {
+                sb.append("    - ").append(s.getUsername()).append("\n");
+            }
+            return sb.toString();
+        }
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        Course course = (Course) obj;
+        return id == course.id;
+    }
+
+    @Override
+    public String toString() {
+        if (teacher != null) {
+            return "[ID:" + id + "] " + name + " (Teacher: " + teacher.getUsername() + ")";
+        } else {
+            return "[ID:" + id + "] " + name + " (No teacher assigned)";
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/models/Student.java b/src/main/java/models/Student.java
new file mode 100644
index 0000000..b8c51a4
--- /dev/null
+++ b/src/main/java/models/Student.java
@@ -0,0 +1,15 @@
+package models;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Student extends User {
+    private List<Course> enrolledCourses;
+
+    public Student(String username, String password) {
+        super(username, password);
+        this.enrolledCourses = new ArrayList<>();
+    }
+
+  //TODO
+}
\ No newline at end of file
diff --git a/src/main/java/models/Teacher.java b/src/main/java/models/Teacher.java
new file mode 100644
index 0000000..9f900fc
--- /dev/null
+++ b/src/main/java/models/Teacher.java
@@ -0,0 +1,53 @@
+package models;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Teacher extends User {
+    private List<Course> myCourses;
+
+    public Teacher(String username, String password) {
+        super(username, password);
+        this.myCourses = new ArrayList<>();
+    }
+
+    public boolean addCourse(Course course) {
+        if (myCourses.contains(course)) {
+            return false;
+        }
+        myCourses.add(course);
+        course.setTeacher(this);
+        return true;
+    }
+
+    public boolean removeCourse(Course course) {
+        if (myCourses.remove(course)) {
+            course.setTeacher(null);
+            return true;
+        }
+        return false;
+    }
+
+    public List<Course> getMyCourses() {
+        return myCourses;
+    }
+
+    public void showMyCourses() {
+        if (myCourses.isEmpty()) {
+            System.out.println(" You don't teach any course yet.");
+        } else {
+            System.out.println("\n My Courses:");
+            for (int i = 0; i < myCourses.size(); i++) {
+                System.out.println("  " + (i+1) + ". " + myCourses.get(i));
+            }
+        }
+    }
+
+    public void showStudentsInCourse(Course course) {
+        if (!myCourses.contains(course)) {
+            System.out.println(" You don't teach this course!");
+            return;
+        }
+        course.showStudents();
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/models/User.java b/src/main/java/models/User.java
new file mode 100644
index 0000000..32c928e
--- /dev/null
+++ b/src/main/java/models/User.java
@@ -0,0 +1,42 @@
+package models;
+
+public abstract class User {
+    protected String username;
+    protected String password;
+
+    public User(String username, String password) {
+        this.username = username;
+        this.password = password;
+    }
+
+    public String getUsername() { return username; }
+
+    public boolean checkPassword(String password) {
+        return this.password.equals(password);
+    }
+
+    public static String validateUsername(String username) {
+        if (username == null || username.trim().isEmpty()) {
+            return "Username cannot be empty!";
+        }
+        if (username.length() < 3) {
+            return "Username must be at least 3 characters!";
+        }
+        return null;
+    }
+
+    public static String validatePassword(String password) {
+        if (password == null || password.length() < 4) {
+            return "Password must be at least 4 characters!";
+        }
+        return null;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        User user = (User) obj;
+        return username.equalsIgnoreCase(user.username);
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/services/SchoolSystem.java b/src/main/java/services/SchoolSystem.java
new file mode 100644
index 0000000..5007246
--- /dev/null
+++ b/src/main/java/services/SchoolSystem.java
@@ -0,0 +1,78 @@
+package services;
+
+import models.*;
+import java.util.ArrayList;
+import java.util.List;
+
+public class SchoolSystem {
+    private List<Student> students;
+    private List<Teacher> teachers;
+    private List<Course> allCourses;
+
+    public SchoolSystem() {
+        this.students = new ArrayList<>();
+        this.teachers = new ArrayList<>();
+        this.allCourses = new ArrayList<>();
+    }
+
+    // ========== Student Management ==========
+   //TODO
+
+    // ========== Teacher Management ==========
+    public boolean registerTeacher(String username, String password) {
+        if (findTeacher(username) != null) {
+            return false;
+        }
+        teachers.add(new Teacher(username, password));
+        return true;
+    }
+
+    public Teacher loginTeacher(String username, String password) {
+        Teacher teacher = findTeacher(username);
+        if (teacher != null && teacher.checkPassword(password)) {
+            return teacher;
+        }
+        return null;
+    }
+
+    private Teacher findTeacher(String username) {
+        for (Teacher t : teachers) {
+            if (t.getUsername().equals(username)) return t;
+        }
+        return null;
+    }
+
+    // ========== Course Management ==========
+    public boolean addCourseToSystem(String courseName) {
+        //TODO
+        return true;
+    }
+
+    public Course findCourseById(int id) {
+       //TODO
+        return null;
+    }
+
+    public Course findCourseByName(String name) {
+        for (Course c : allCourses) {
+            if (c.getName().equalsIgnoreCase(name)) return c;
+        }
+        return null;
+    }
+
+    public String getAllCoursesDisplay() {
+        if (allCourses.isEmpty()) {
+            return " No courses available yet.";
+        } else {
+            StringBuilder sb = new StringBuilder("\n All Available Courses:\n");
+            for (int i = 0; i < allCourses.size(); i++) {
+                sb.append("  ").append(i+1).append(". ").append(allCourses.get(i)).append("\n");
+            }
+            return sb.toString();
+        }
+    }
+
+    public List<Course> getAllCourses() {
+        return allCourses;
+    }
+}
\ No newline at end of file