Remove the screws that hold the face plate onto the wall. Pull the face plate away from the wall and set it aside.
Remove the faucet or handle if it is in the way by unscrewing it from the cartridge. If it isn't in the way of the stops, you can leave it on.
Unscrew the existing MCSVS stops from their pipes on either side of the faucet. Turn the stops counter-clockwise to remove them.
Screw the new MCSVS stops into the pipes by turning them clockwise. Don't tighten them all the way or you will cut off the water flow to the faucet.
Replace the faucet and face plate and screw them both into place.