Mobile GUI Buttons

I am making a game for IOS, and I want a button to be able to send output to a gameobject. For example, when the UI button is touched, the camera would move up. My button can read inputs from touch, but cannot broadcast them to the gameobject. My script is:

using UnityEngine;
using System.Collections;

public class Test: MonoBehaviour 
{

	void OnMouseDown() 
	{
		Debug.Log ("Mouse Down");
		}

	void OnMouseUp() 
		{
		Debug.Log ("Mouse up");
	}
	
}

Should I use global variables? I cannot find anything like this for a button in ios. Thank you for your time.

With UI Button attach this script to the Button then Under OnClick tab press " + " to the object choose " button " and under Function → test3 → ClickTest()
using UnityEngine;
using System.Collections;

public class test3 : MonoBehaviour
{
	public void ClickTest()
	{
		Debug.Log("Clicked !");
	}	
}