Turn off the sink's hot and cold water valves. Drain the lines by opening the faucet.
Use an adjustable wrench to disconnect the faucet water supply lines. Disconnect drains. Put a bucket under to catch water. Cut the caulk connecting the old sink to the countertop with a tool knife.
Clean the new sink's countertop. Make sure the new sink fits. You may need to alter the countertop cutout.
Apply silicone sealant or plumber's putty to the sink cutout or rim.
Put the new sink down. It should sit evenly on the countertop. Install the sink-to-countertop mounting clips from underneath. Tighten clips with a tool or screwdriver.
Drain assembly to sink drain outlet. Plumbers tape seals threads waterproof. Reconnect drains. Run water through the sink to check for leaks.
Wrenches the water supply lines to the faucet. Keep connections tight but not over-tightened.
Restart the water and inspect the faucet and drain connections for leakage. Remove extra sealant around the sink if there are no leaks.
Clean up tools and caulk. The sink should work now.