how to make dialog box and how can i scroll the text using UI GUI buttons in Android / Touch

So first how can i convert getkeys to touch in " if (Input.anyKeyDown(KeyCode.Return))"

i want to touch the button as a continue button. but how can i do that using UI Buttons?

using UnityEngine; using System.Collections; using UnityEngine.UI;

public class TextBoxManager : MonoBehaviour {

 public GameObject textBox;
 public Text theText;

 public TextAsset textFile;
 public string [] textLines;

 public int currentLine;
 public int endAtLine;

 public FloatingPlayer2DController player;

 void Start()
 {
     player = FindObjectOfType<FloatingPlayer2DController> ();

     if(textFile !=null)
     {
         textLines = (textFile.text.Split('\n'));
     }
     if (endAtLine == 0) 
     {
         endAtLine = textLines.Length - 1;

     }
 }
 void Update()
 {
     theText.text = textLines [currentLine];
     if (Input.anyKeyDown(KeyCode.Return))

     {
         currentLine += 1;
     }
     if (currentLine > endAtLine) 
     {
         textBox.SetActive(false);
     }
 }

}