2D horizontal ball movement

Hello, this is my first post so I hope you can help with my problem.
Im making an android game, and I want to move a ball after you touch the devices screen. For instance,
if you want to move the ball to the right you have to touch the right side of the screen and the same to the left.
I would be realy thanksful if you help me with that.

Im sorry for my english because im from Argentina.

Thank you.

 

So you problem is detect where user touch screen?
You can try this:

Code (CSharp):

1.     private void Update()
2.     {
3.         // Mouse
4.         if (Input.GetMouseButtonDown(0))
5.         {
6.             if (Input.mousePosition.x >= Screen.width / 2)
7.                 Debug.Log("Right");
8.             else
9.                 Debug.Log("Left");
10.         }
11.  
12.         // Touch
13.         if (Input.touchCount == 1)
14.         {
15.             Touch currentTouch = Input.GetTouch(0);
16.  
17.             if (currentTouch.phase == TouchPhase.Began)
18.             {
19.                 if (currentTouch.position.x >= Screen.width / 2)
20.                     Debug.Log("Right");
21.                 else
22.                     Debug.Log("Left");
23.             }
24.         }
25.     }