How to drag the 3D model in screen with finger

I'm doing vuforia + unity apps. I have displayed the 3D model in the screen and referred the script from here https://developer.vuforia.com/resources/dev-guide/unity-drag-ar-object-screen-your-finger for drag the 3D model in the screen but nothing happen when i touch the screen and drag. Please check screenshot also

 using UnityEngine;
 using System;
 
 public class DynamicModelsGUI : MonoBehaviour
 {    
     private GameObject metaioMan;
     public GUIStyle buttonTextStyle;
     float SizeFactor;
     
     // variables for ray tracing
     private RaycastHit hit;
     private LayerMask layerMask = 1<<4;
 
     private bool selected = false;
     private Vector3 offset = new Vector3(0.0f, 0.0f, 0.0f);
     
     void Start() 
     {
         SizeFactor = GUIUtilities.SizeFactor;
         
         // Find metaioman object
         metaioMan = GameObject.Find("HMI_Mirra_3D");
     }
     
     // Update is called once per frame
     void Update()
     {    
         SizeFactor = GUIUtilities.SizeFactor;
     
         // only handle touchs or clicks when metaioman is active, i.e.
         // is visible on tracking pattern
         if (metaioMan.active)
         {
             if (Input.touchCount > 0)
                 // if tracking, then evaluate touch point
                 handleTouches();
             else if (Input.GetMouseButton(0))
                 handleClicks();
             else
                 selected = false;
         }
     }
     
     private void handleTouches()
     {
         // if there's touch points and the phase is began-->try to select the geometry
         if(Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Began)
             selectGameObject(Input.GetTouch(0).position);
         
         // if the touch point is moving and metaio man is selected
         if(Input.GetTouch(0).phase == TouchPhase.Moved && selected)
             moveGameObject(Input.GetTouch(0).position);
         else if(Input.GetTouch(0).phase == TouchPhase.Ended)
             // deselect metaio man if touch has ended
             selected = false;
     }
     
     public void handleClicks()
     {
         // if there's left mouse click-->try to select the geometry
         if (!selected && Input.GetMouseButtonDown(0))
             selectGameObject(Input.mousePosition);
         
         if (selected && Input.GetMouseButton(0))
             moveGameObject(Input.mousePosition);
     }
     
     public void selectGameObject(Vector2 position)
     {
         // get a ray from the touch point
         Ray ray = Camera.main.ScreenPointToRay(position);
             
         // layer mask, metaio man is on layer 4
         layerMask = 1<<4;
             
         // cast a ray on layer 4, if metaio man has been hit
         if (Physics.Raycast(ray, out hit, 5000, layerMask) && hit.collider.gameObject.name == "HMI_Mirra_3D")
         {
             // metaio man is touched --> select it
             selected = true;
                 
             // swith to layer 8, find the initial touch point on the plane and use it as a reference
             layerMask = 1<<8;
             if (Physics.Raycast(ray, out hit, 5000, layerMask))
             {
                 // record the offset of the touch point and the object position point
                 offset = hit.point - metaioMan.transform.position;
             }
         }
         else
             // not hit, don't select
             selected = false;
     }
     
     public void moveGameObject(Vector2 position)
     {
         // cast a ray on layer 8 (the plane) to calculate the hit position of the plane
         Ray ray = Camera.main.ScreenPointToRay(position);
         layerMask = 1<<8;
         if(Physics.Raycast(ray, out hit, 5000, layerMask) && hit.collider.gameObject.name == "HMI_Mirra_3D")
         {
             // move the metaio man to the intersect of the ray and the plane, offset should be accounted for
             metaioMan.transform.position = hit.point - offset;
         }
     }
     
     public void OnGUI()
     {
         if(GUIUtilities.ButtonWithText(new Rect(
             Screen.width - 200*SizeFactor,
             0,
             200*SizeFactor,
             100*SizeFactor),"Back",null,buttonTextStyle) ||    Input.GetKeyDown(KeyCode.Escape)) {
             PlayerPrefs.SetInt("backFromARScene", 1);
             Application.LoadLevel("MainMenu");
         }        
     }
 }