To install a drop-in bathroom sink, check for clearance, mark the cutout, cut the hole, install the sink and connect it to the plumbing. The tools and supplies you need include an electric drill, a jigsaw, a pipe wrench, an adjustable wrench, and the appropriate silicone caulk and waterproof epoxy compound. A tape measure and a pencil are required as well.
Measure the sink on all sides and make sure there is enough room on the countertop and inside the cabinet to accommodate the sink and the attached plumbing pipes. Turn the sink upside down and place the rim in position on the countertop. Mark the outside edge of the sink and lift the sink out of the way. Drill a pilot hole 1/2 inch inside of the line and big enough to fit the jigsaw blade through. Cut out the countertop with the jigsaw, maintaining the cut line 1/2 inch inside the marked perimeter.
Clean the countertop thoroughly to remove all of the sawdust. Attach the drain piece and its collar through the drain hole on the sink. Apply silicone plumbing caulk liberally around the underside of the sink rim and set the sink down into the hole. Press it firmly in place and wipe off any excess caulk that squeezes out.
If the sink is equipped with retaining clips, use the epoxy to secure the clips in place underneath the counter. Insert and tighten any screws necessary to complete the clip mounting.
Attach the faucet and handles using silicone to seal the seats. Connect the water and drain lines to complete the process.