Load next level from array ?

I want to load the next level from array!

I made something like this :-

function OnTriggerEnter (other : Collider) { 	
    if(other.gameObject.CompareTag("End")) {
    	yield WaitForSeconds(1);

It loaded the 2nd level. But in the 2nd level, it doesn’t load the 3rd level when enter the trigger as i needed. But it loaded the 2nd level again. How do i do as i wanted ?

Closed as duplicate.