Buttons to make the ball move left and right

Hello Forum, I have a question about the UI Buttons in unity. Firstly, I have made all the buttons, as you can see in the picture below, and I have added the Jump function to the jump button using OnClick, which works perfectly, but the only problem is, I don't know how to do the same for the left and right button, so that the ball rotates and moves left and right using OnClick, that would be great. So if someone could send me a tweaked version of my script below, with the left and right button movement function, that would be much appreciated. Thanks in advance.!

 #pragma strict
  #pragma strict
   
   var rotationSpeed = 100;
   var jumpHeight = 0.1;
   
   var Hit01 : AudioClip;
   var Hit02 : AudioClip;
   var Hit03 : AudioClip;
 
   var distToGround : float;
   
   function Start() {
       distToGround = GetComponent.<Collider>().bounds.extents.y;
     }
   
   function Update () 
   {
       
      //Handel ball roation (right; left) 
       var rotation : float = Input.GetAxis ("Horizontal") * rotationSpeed;
       rotation *= Time.deltaTime;
       GetComponent.<Rigidbody>().AddRelativeTorque (Vector3.back * rotation);
   
         if (Input.GetKeyDown(KeyCode.UpArrow) && IsGrounded ())
       
       {
           playerJump();
       }
     }
   
   function playerJump(){
   if (IsGrounded ())
        
             {
            GetComponent.<Rigidbody>().velocity.y = jumpHeight;
        }
   }
   
     function IsGrounded () : boolean {
       return Physics.Raycast(transform.position, -Vector3.up, distToGround + 0.1);
   }
   
   function OnCollisionEnter () {
         var theHit = Random.Range(0, 3);
       if (theHit == 0)
       {
           GetComponent.<AudioSource>().clip = Hit01;
       }
         else if (theHit == 1)
       {
           GetComponent.<AudioSource>().clip = Hit02;
       }
       else {
       GetComponent.<AudioSource>().clip = Hit03;
       }
       GetComponent.<AudioSource>().pitch = Random.Range (0.9,1.1);
       GetComponent.<AudioSource>().Play();
   }