Remove the old shower head. Clean the threads of the pipe protruding from the shower wall with steel wool.
Apply Teflon tape to the pipe threads to ensure a snug, waterproof fit of the new overhead shower head.
Attach the mounting hardware to the pipe protruding from the shower. This will vary depending on the manufacturer. Regardless, ensure the hardware is screwed onto the pipe tightly. Attach the extension pipe, if applicable, to the hardware. Use a wrench to tighten the extension pipe.
Attach the overhead shower head by hand, and raise or lower it into the desired position. Tighten the wing nut to secure the overhead shower head in place. Do not use a wrench at this point; tighten only by hand to avoid damaging the overhead shower head.