Before time in my game start. i want there will show a guiTexture.. if i touch this guiTexture, that will hidden and the time game will start. I try to make a script but it doesn't work. I'm a bit confused by the Unity documentation. please help me i'm newbie in Unity.

my code :

void Start () {
    if (myGuiTexture.HitTest(Input.GetTouch(0).position))
    {
        if (Input.GetTouch(0).phase == TouchPhase.Began)
        {
            Time.timeScale = 1;
            myGuiTexture.enable = false;
        }
    }
}

and i also create this source but its doesn't work too.

void Start () {
    if (tutorial.HitTest(new Vector3(0,0,0))){
        Time.timeScale = 1;
    }

}