Remove the old drain pipe. Remove the old drain assembly from the top down. Attach new tailpiece. â€¢ Add a T-fitting (if necessary) â€¢ Attach the trap arm. Attach the trap arm to the drain stub-out, using a slip nut and washer. Connect trap bend to the trap arm.
The curvy pipe under your sink is called the P–trap. It's designed to prevent noxious gases from backing up through a drain by holding water in the bend, sealing .
The P trap connects to a horizontal pipe that connects to the drain pipe in the wall
Install the Sink. Assemble the faucet and drain on the sink before you install it on the vanity. Add a thin bead of silicone adhesive to the rim of the sink opening in the vanity. With the help of another person, carefully set the sink top on the vanity, making sure the plumbing is lined up.