Missing Component Exception Error

I was new to Unity and was watching other people's lectures. However, the lecture uses a little older version of Unity and VirtualStudio and is having difficulty with progress.

     tempBallPos = collider.Transform.Position;
     tempBallScale = collider.Transform.Position;

However, it says >> colider << is no longer used so I changed it to-

     tempBallPos = GetComponent <Collider> (). transform.position;
     tempBallScale = GetComponent <Collider> (). transform.position;

But this time 'MissingComponentException: There is no 'Collider' attached to the "1" object, but a script is try to access it. You probably need to add a collider to the game object "1". component is attached before using it.' Error occurs. I do not know what to do.