need help plz array index out of range

Unity Engine
1

so im getting the error
IndexOutOfRangeException: Array index is out of range.
Inventory.Start () (at Assets/Scripts/Inventory.js:14)

here is the code, i diont understand what is the problem
import System.Collections.Generic;

import System.Collections.Generic;

//Holding all of our items.
var items : Item[];
//Inventory
var MainInventory : List.<Item> = new List.<Item>();


function Start(){
    MainInventory.Add(items[0]);
}

function OnGUI(){


}
2

No items have been assigned in the items array.

If you have assigned an item, check that this script hasn’t been placed multiple times.

3

the items get added in the inspector, and the script has only been placed once

4

ok my bad the script was placed twice, thank you