Step 2 · Disconnect Existing Drain Plumbing
Using a pair of channel-lock pliers, loosen the large slip nuts that connect the P-trap (the U-shaped pipe) to the sink's tailpiece and the drain arm extending into the wall. Once the nuts are loose, you should be able to unscrew them by hand. Carefully wiggle the P-trap free and empty any remaining water into the bucket. Then, remove the horizontal drain arm from the wall pipe.