Close the main water valve to shut off the water in the house. Open another faucet all the way to test that the water flow has ceased, as well as to relieve any pressure left in the plumbing.
Locate the screw that holds the faucet's handle in place, normally located at the base of the handle or underneath a plastic decorative cap in the middle of the handle. Use a screwdriver to remove the screw, then pull the handle off the faucet.
Use a wrench to remove any nuts or plastic adapter rings from the valve cartridge. Use a pair of needle nose pliers to pull out any metal retaining clips or pins from the middle or side of the cartridge.
Place either a wrench or the handle over the cartridge and turn counterclockwise to remove the cartridge from the water pipe. Remove the screws that anchor the faucet's back plate to the wall and remove the back plate.
Assemble the new faucet in the reverse order that you used to remove the old faucet, starting with the back plate. Once you have secured the handle, open the house's water valve and check the faucet for any leaks.