Help with Script

I am having issues with my “Loot System”, can someone show me the mistakes I made? I am using the BergZerg Arcade tutorials. Here is script so far. Any help would be appreciated. Thanks!

    using UnityEngine;
using System.Collections;
using System.Collections.Generic;

public class myGUI : MonoBehaviour {
 public float lootWindowHeight = 90;
 
 public float buttonWidth = 40;
 public float buttonHeight = 40;
 private IList  _lootItems;
 private float _offset = 10;
 private const int LOOT_WINDOW_ID = 0;
 private Rect _lootWindowRect = new Rect(0,0,0,0);
 
 // Use this for initialization
 void Start () {}
 _lootItems = new List<_lootItems>();
 
 Populate();
 
 // Update is called once per frame
 void Update () {
 }
 
 void OnGUI() {
        _lootWindowRect = GUI.Window(LOOT_WINDOW_ID, new Rect(_offset, Screen.height - (_offset + lootWindowHeight), Screen.width - (_offset * 2), lootWindowHeight), LootWindow, "Loot Window");
 }

 private void LootWindow(int id) { 
 for(int cnt = 0; cnt < _lootItems.Count; cnt++) {
 GUI.Button (new Rect(buttonWidth * cnt, 0,buttonWidth, butonHeight); cnt.ToString());
    }


 private void Populate() {
 for(int cnt = 0; cnt < 25; cnt++)
 _lootItems.Add(new Item());
}

Populate();

Are you trying to call this in start?

Start does nothing

   void Start () {}

I think you meant to put the Populate Call and the instantiation of _lootitems in start but didn’t realize start was closed.

Here are the actual errors on the lines:

_lootItems = new List<Item>(); Error: Invalid token '=' in class, struct, or interface member declaration. Other error: Invalid token '(' in class, struct, or interface member declaration.
void Update () { Error: A namespace does not directly contain members such as fields or methods. 
_lootWindowRect = GUI.Window(LOOT_WINDOW_ID, new Rect(_offset, Screen.height - (_offset + lootWindowHeight), Screen.width - (_offset * 2), lootWindowHeight), LootWindow, "Loot Window"); Error: Expected class, delegate, enum, interface, or struct. } Error: Type or namespace definition or end-of-file expected.

with private List _lootItems
I get an error saying "The type or namespace name ‘Item’ could not be found (are u missing a using directive or an assembly reference?)