To install a kitchen countertop, level the cabinets, measure the countertop area's dimensions, and cut the countertop accordingly. Then, cut holes in the countertop for the sink and its fixtures. Position and seal the countertop over the cabinets, and fix the sink in the hole.
To level the cabinets, use a 4-foot level to check the level of two cabinets at a time. Then, place shim under the cabinet that is at a lower level, and screw the two cabinets together at the stile using deck screws. Level all the cabinets in this manner.
When measuring the length and breadth of the countertop area, include the desired overhang distance. To cut the countertop according to this measurement, place the top on two 2-by-4 boards, and cut with a diamond-bladed circular saw.
To cut the hole for the sink, determine the distance between the cabinet's end and the sink's beginning. Also, measure the sink's length and width, and mark all these measurements on the cut countertop. Then, drill four holes at the sink's corners marked on the countertop with an electric drill containing a diamond hole saw. Next, position two 2-by-4 boards over a couple of saw horses, and secure the countertop over the boards. Now, cut the sink's shorter sides first and then the longer sides using a metal-bladed jigsaw.
After drilling holes for the sink's faucet, sand the countertop's edges using a 100-grit sandpaper, and smooth them with 200-grit sandpaper.
When positioning the countertop over the cabinets, place it against the wall. Position the sink within the hole cut for it, apply silicone beneath the flange, and push the sink to fix it in place. Finally, apply silicone sealant to seal the gap between the countertop and the cabinets.