Steps. 1  1. Turn off the hot and cold water lines. 2  2. Turn on the existing faucet. 3  3. Detach the existing faucet from the sink.  4. Clean the sink 1  surface. 5. Place new putty onto the new deck plate.  6. Place the new deck plate and 1  faucet. 7. Install the washers and mounting hardware.  8. Clean 1  the area. 9. Connect the water supply  lines.