Turn off the water in the shower at the knob or handle.
Remove the old showerhead by twisting the metal nut on the back of the head counterclockwise with a wrench to disengage it from the wall pipe. Clean the pipe threads with an old cloth.
Wrap plumber's tape around the threading on the wall pipe. Press the white tape into the threads and trim any excess with scissors.
Attach the female end of the flexible steel hose to the wrapped threading on the wall pipe. Snug it by hand and tighten with pliers.
Wrap tape around the threads on the male end of the flexible steel hose.
Attach the rotating nut on the end of the dual shower head to the male end of the flexible hose. Tighten the nut with pliers.
Attach the dual showerhead to the wall pipe with the Y-shaped clip supplied with the shower head.
Turn on the shower to check for leaks at any of the connections. Tighten the connections with the wrench to eliminate any dripping water.