Unscrew the screw on the top of the drain cap with a screwdriver and remove the drain cap.
Insert the drain extractor into the drain in the closed position with the arms in the cylinder. Attach the socket wrench to the top of the extractor by placing the socket over the bit in the top of the extractor. Turn the socket wrench to the loosen setting.
Push the socket wrench bar counterclockwise (to the left) to dethread the drain. This requires pressure to break the seal of the putty and hard water deposits holding the drain in place. Unscrew the drain and remove it from the shower floor.
Apply plumber's putty along the bottom rim of the new drain. Place the new drain into the shower drain pipe. Insert the drain extractor tool in the drain. Set the socket wrench to tighten by turning the button on the top to the right.
Tighten the drain by turning the socket wrench bar to the right until the drain is threaded onto the pipe. Apply force, but do not overtighten the drain.