diff --git a/src/main/java/com/booleanuk/core/Basket.java b/src/main/java/com/booleanuk/core/Basket.java
index df7a20aa..899e592d 100644
--- a/src/main/java/com/booleanuk/core/Basket.java
+++ b/src/main/java/com/booleanuk/core/Basket.java
@@ -1,5 +1,74 @@
 package com.booleanuk.core;
 
+
+import java.util.HashMap;
+
 public class Basket {
+    // TODO: Difference between ArrayList and simple List??
+    // TODO: Should this be private variables?
+    HashMap<String, Integer> products;
+    int maxCapacity;
+    int size = 0;
+
+    public Basket() {
+        this.products = new HashMap<>();
+        this.maxCapacity = 3;
+    }
+
+    public boolean add(String productName) {
+        // Check if max capacity
+        if (this.size >= maxCapacity) {
+            System.out.println("Basket is full, can't add more items.");
+            return false;
+        }
+
+        // List properties
+        int numOfProducts;
+
+        // Update numOfProducts if already exist, otherwise just add
+        if (products.containsKey(productName)) {
+            numOfProducts = products.get(productName) + 1;
+        } else {
+            numOfProducts = 1;
+        }
+
+        // Add product
+        products.put(productName, numOfProducts);
+
+        // Update size
+        size++;
+
+        return true;
+    }
+
+    public boolean remove(String productName) {
+
+        // Check if product does not exist
+        if (!this.products.containsKey(productName)) {
+            System.out.println("Product does not exist. Can't remove.");
+            return false;
+        }
+
+        // Update quantity if already in list, remove if it is the last product in this type/category
+        int newNumOfProducts = this.products.get(productName) - 1;
+        if (newNumOfProducts == 0) {
+            this.products.remove(productName);
+        } else {
+            this.products.put(productName, newNumOfProducts);
+        }
+
+        // Update size
+        size--;
+
+        return true;
+    }
 
+    public boolean changeCapacity(int newMaxCapacity) {
+        if (newMaxCapacity < 1) {
+            System.out.println("Invalid max capacity. Can't be less than 1");
+            return false;
+        }
+        this.maxCapacity = newMaxCapacity;
+        return true;
+    }
 }
diff --git a/src/main/java/com/booleanuk/core/Domain.md b/src/main/java/com/booleanuk/core/Domain.md
new file mode 100644
index 00000000..d0a2b75d
--- /dev/null
+++ b/src/main/java/com/booleanuk/core/Domain.md
@@ -0,0 +1,9 @@
+| Classes                        | Variables                             | Methods                           | Scenario                                      | Outcome                           |
+|--------------------------------|---------------------------------------|-----------------------------------|-----------------------------------------------|-----------------------------------|
+| `Basket` | `HashMap<String, Integer> products`   | `add(String productName)`         | Item succesfully added.                       | true                              |
+|                                |                                       |                                   | Basket is full. Item could not be added.      | false, Error: Basket is full                              |
+|                                |                                       | `remove(String productName)`      | Item is in basket and can be removed.         | true                              |
+|                                |                                       |                                   | Item is not in basket and can not be removed. | false, Error: Item does not exist |
+|                                | `int maxCapacity`                     | `changeCapacity(int newCapacity)` | If newCapacity is more than 0.                | true                              |
+|                                |                                       |                                   | If newCapacity is less than 1.                | false                             |
+    
diff --git a/src/test/java/com/booleanuk/core/BasketTest.java b/src/test/java/com/booleanuk/core/BasketTest.java
index e35771b3..2a85783c 100644
--- a/src/test/java/com/booleanuk/core/BasketTest.java
+++ b/src/test/java/com/booleanuk/core/BasketTest.java
@@ -3,6 +3,53 @@
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
+import java.util.ArrayList;
+import java.util.HashMap;
+
 class BasketTest {
 
+    // User story 1.
+    @Test
+    public void add() {
+        Basket basket = new Basket();
+        Assertions.assertTrue(basket.add("Unicorn Bagel"));
+        Assertions.assertEquals(1, basket.size);
+
+        basket.add("Unicorn Bagel");
+        Assertions.assertEquals(2, basket.products.get("Unicorn Bagel"));    // Index 0 is numOfProducts
+
+        basket.add("Sunhaven Bagel");
+        Assertions.assertFalse(basket.add("Moon Bagel"));    // Exceed maxCapacity
+    }
+
+    @Test
+    public void remove() {
+        Basket basket = new Basket();
+        basket.add("Small Bagel");
+        basket.add("Small Bagel");
+
+        // Remove first item, 1 left
+        Assertions.assertTrue(basket.remove("Small Bagel"));
+        Assertions.assertEquals(1, basket.products.get("Small Bagel"));
+
+        // Remove second item, 0 left (should be removed from list)
+        Assertions.assertTrue(basket.remove("Small Bagel"));
+        Assertions.assertFalse(basket.products.containsKey("Small Bagel"));
+
+        // Remove not existing item
+        Assertions.assertFalse(basket.remove("Small Bagel"));
+    }
+
+    @Test
+    public void changeCapacity() {
+        Basket basket = new Basket();
+
+        // Change to valid max capacity
+        Assertions.assertTrue(basket.changeCapacity(5));
+        Assertions.assertEquals(5, basket.maxCapacity);
+
+        // Change to invalid max capacity
+        Assertions.assertFalse(basket.changeCapacity(0));
+        Assertions.assertFalse(basket.changeCapacity(-1));
+    }
 }