Any owner of a house should be able to fix shower faucet that is broken or leaking. It only takes a little time and some household tools. Closes all the water supply to the shower. Open faucets and let the water drain pipes completely. This will eliminate the chance that the water will splash or spill while arrangements are made. Locate the screw on the knob. Remove it carefully with a flathead screwdriver. Unclips the screw and remove the faucet knob with the appropriate screwdriver.
Most losses are due to wear of rubber gaskets. Replace the knob when fix shower faucet, reopen the water and see if the dripping stopped. Otherwise, make sure the package is the right size or try to adjust the tap a little more. If broken, follow steps from fix shower faucet 1-3 but removes all parts tap for shower.
Bring the parties to a trade of spare parts for plumbing so you can be sure you buy the parts indicated. Install a new faucet. You just install the shower tap which was above if there are no instructions on replacement parts. The screw holes will already be there and just be a matter to fit each part where it belongs.