How do i need to change this script for mobile?

This is a script for collecting pages like in slender. The problem is that i wan't to make this for android and i don't know how to, can anybody help? (it's java script just if you don't know)

 @script RequireComponent ( AudioSource )
 var papers : int = 0; 
 var papersToWin = 5; 
 var distanceToPaper : float = 2.5; 
 public var paperPickup : AudioClip; 
 
 function Start () 
 { 
     Screen.lockCursor = true; 
 } 
 
 function Update () 
 { 
     if(Input.GetMouseButtonDown (0) || Input.GetKeyDown (KeyCode.E)) 
     { 
         var ray = Camera.main.ScreenPointToRay(Vector3(Screen.width * 0.5, Screen.height * 0.5, 0.0)); 
         var hit : RaycastHit; 
     
         if(Physics.Raycast(ray, hit, distanceToPaper)) 
         { 
             if(hit.collider.gameObject.name == "Paper") 
             { 
                 papers += 1; audio.PlayClipAtPoint(paperPickup, transform.position); 
                 Destroy(hit.collider.gameObject); 
             } 
         } 
     } 
 }
  
 function OnGUI () 
 { 
     if(papers < papersToWin) 
     { 
         GUI.Box(Rect((Screen.width * 0.5) -60, 10, 120, 25), " " + papers.ToString() + " papers");
     } 
     
     else 
         GUI.Box(Rect((Screen.width/2) - 100, 10, 200, 35), "All Papers Collected!"); 
 }