Remove the arrow selector handle or valve handle that says Z3. You should see a square nub that the valve handle connects to. There is a circular ring around this valve that can he unscrewed. Usually it can be done by hand. After you get the circular collar off, you will see the square nub and more of the valve. Usually the valve can be pulled out by hand, but if it can't, you should get some pliers and pull straight up on it. Try and grab the circular post that the square nub is mounted to, rather than grabbing the square nub, because if you disform the nub, the handle might not go back on properly.
