diff --git a/index.js b/index.js
index 0f4b28b4..d25bd769 100644
--- a/index.js
+++ b/index.js
@@ -1,17 +1,85 @@
 class SortedList {
-  constructor() {}
+  constructor(items, length) {
+    this.items = [];
+    this.length = 0;
+  }
 
-  add(item) {}
+  add(item) {
+    // ADD THE NEW ITEM TO THE END OF THE ARRAY
+    this.items.push(item);
 
-  get(pos) {}
+    //INCREMENT THE LENGTH PROPERTY MANUALLY
+    this.length++;
 
-  max() {}
+    //SORT THE ENTIRE ARRAY USING A NUMERIC COMPARATOR
+    this.items.sort((a, b) => a - b);
+  }
 
-  min() {}
+  get(pos) {
+    // CHECK THE LOWER BOUND: POSITION MUST BE 0 OR GREATER 
+    // THE UPPER BOUND: POSITION MUST BE LESS THAT THE TOTAL LENGTH
 
-  sum() {}
+    if(pos >= 0 && pos < this.length ){
+     // THE CODE RUNS ONLY IF BOTH CONDITIONS ARE TRUE
 
-  avg() {}
+     //THE POSITION IS VALID (WITHIN BOUNDS)
+     return this.items[pos];   
+    }else {
+      // THE POSITION IS INVALID (OUT OF BOUNDS)
+      //STOPING THE FUCTION IMMEDIATELY AND "THROW" AN EXCEPTION 
+      throw new OutOfBoundsError(`OutOfBoundsError: Position ${pos} is out of bounds of the list.`)
+    }
+  }
+
+  max() {
+    if(this.length === 0){
+      //IF EMPTY, IMMEDIETLY THROW THE REQUIRED ERROR/EXECPTION
+      throw new Error("EmptySortedListError: Cannot find max value in an empty list.");
+    }
+
+    //IF THE LIST IS NOT EMPTY, RETURN THE LAST ELEMENT
+    //SINCE THE LIST IS SORTED, THE HIGHEST VALUE IS ALWAYS THE LAST INDEX (LENGTH -1)
+    return this.items[this.length -1];
+  }
+
+  min() {
+    if(this.length === 0){
+      throw new Error("EmptySortedList: Cannot find min value in an empty list.")
+    }
+    //BECAUSE THE LIST IS SORTED, THE MINIMUM VALUE IS ALWAYS THE FIRST ELEMENT (INDEX 0) 
+    return this.items[0];
+  }
+
+  sum() {
+    
+    //RETURNING 0 FOR THE EMPTY SORTED LIST
+    if(this.length === 0 ){
+      return 0;
+    }
+
+
+    //"REDUCE" TAKES A CALL BACK FUNCTION (ACCUMULATOR, CURRENTVALUE) =>...
+    //THE SECOND ARGUMENT '0' IS THE STARTING VALUE OF THE ACCUMULATOR
+     const totalSum = this.items.reduce((accumulator, currentValue) => {
+      return accumulator + currentValue;
+     }, 0);
+
+     return totalSum;
+  }
+
+  avg() {
+    
+    //RETURNING THE EMPTY LIST IF THERE IS NO ELEMET
+    if(this.length === 0){
+      throw new EmptySortedList("EmptySortedList: Cannot find the element in the list")
+    }
+
+    //CALCULATE THE SUM OF ALL ELEMENTS (REUSING THE SUM() METHOD IS CLEANER)
+    const total = this.sum();
+
+    //Divide the total sum by the number of items
+    return total / this.length;
+  }
 }
 
 module.exports = SortedList;
diff --git a/package.json b/package.json
index 3a5127ae..f2ff4434 100644
--- a/package.json
+++ b/package.json
@@ -19,5 +19,8 @@
     "intro"
   ],
   "author": "fer@ironhack.com",
-  "license": "MIT"
+  "license": "MIT",
+  "dependencies": {
+    "mocha": "^11.7.5"
+  }
 }