Replace an outdoor faucet by turning off the water supply and draining the line. Remove the old faucet by unscrewing it from the pipe inside the wall. Apply plumber tape to the new faucet threads and screw it into the pipe fitting hand tight then one additional turn with a wrench. Install a frost-free sillcock if you live in a freezing climate. Caulk around the exterior wall penetration to prevent air and water infiltration. Turn on water and check for leaks.