Here are the steps to install a shower head:
1. Turn off the water supply.
2. Remove the old shower head.
3. Wrap plumber's pipe-seal tape around the threads of the pipe and the shower head to prevent leaks.
4. Attach a diverter unit, a shower hose, or a shower arm depending on the type of shower head you have.
5. Screw the shower head by hand or use an adjustable wrench for some parts.
6. Follow the manufacturer's instructions for any special steps.
7. Test the shower head for leaks and tighten as necessary.
I hope that helps! Let me know if you have any other questions.