Please help me solve the problem with shoot a gun(HTC VIVE)

How to attach shooting gun to my eyes???(HTC vive) When I press the button on the controller, it should fire from my eyes. But it doesn’t work! please help me what to do!! I really need your help!
Please save my life -------------> click on the link: - YouTube

There are two scrips(1. VRYK_ObjectAutoGrab//2.Gun) to attach the gun to front view of camera.

// 1. VRYK_ObjectAutoGrab

namespace VRTK { using UnityEngine; using System.Collections;

public class VRTK_ObjectAutoGrab : MonoBehaviour
{
public VRTK_InteractableObject objectToGrab;
public bool cloneGrabbedObject;

 private VRTK_InteractGrab controller;

 private IEnumerator Start()
 {
     controller = GetComponent<VRTK_InteractGrab>();
     if (!controller)
     {
         Debug.LogError("The VRTK_InteractGrab script is required to be attached to the controller along with this script.");
         yield break;
     }

     

     VRTK_InteractableObject grabbableObject = objectToGrab;
     if (cloneGrabbedObject)
     {
         grabbableObject = Instantiate(objectToGrab);
     }
     controller.GetComponent<VRTK_InteractTouch>().ForceStopTouching();
     controller.GetComponent<VRTK_InteractTouch>().ForceTouch(grabbableObject.gameObject);
     controller.AttemptGrab();
 }

}
}

//2. Gun

using UnityEngine; using VRTK;

public class Gun : VRTK_InteractableObject { public static Camera main; private GameObject bullet; private float bulletSpeed = 2000f; private float bulletLife = 1f; private AudioSource gunAudio;

public override void StartUsing(GameObject usingObject)
{
main = GetComponentInParent();
base.StartUsing(usingObject);
FireBullet();
}

protected override void Start()
{
gunAudio = GetComponent();
base.Start();
bullet = transform.Find(“Bullet”).gameObject;
bullet.SetActive(false);
}

private void FireBullet()
{
GameObject bulletClone = Instantiate(bullet, bullet.transform.position, bullet.transform.rotation) as GameObject;
bulletClone.SetActive(true);
Rigidbody rb = bulletClone.GetComponent();
rb.AddForce(-bullet.transform.forward * bulletSpeed);
Destroy(bulletClone, bulletLife);
}
}

I think it has something to do with the script(1.objectautograb). In that part, I need to arrange the transform and position to attach the object (gun) to Camera eyes (not comera body)
Could you let me know how to do that???please?