Read the shower head's instructions carefully to familiarize yourself with the product's specific installation requirements. Screw the shower head's hose into the bathtub's faucet if it is a screw-on type. Wrap the hose's threads with Teflon tape if you have problems with leaking, then screw it back in place. Tighten the hose with a pair of pliers. If the shower head is a slip-on, place the rubber gasket over the faucet, using pliers to pull it in place if you can't manage it using just your fingers.
Screw the shower head onto the opposite end of the hose if it isn't already attached. Wrap the threads with Teflon tape if you have issues with leaking.
Attach the shower head's holder to your bathtub's wall. Moisten the holder's suction cups, then press it to the wall. Some holders hook onto the shower curtain rod instead of attaching to the wall using suction cups; in this case, simply hook it over the curtain rod, then hang the shower head in the holder.