Measure and dry-fit the sink under the countertop
Mark the sink outline and mounting clip locations
Clean the underside of the countertop and the sink rim
Apply a continuous bead of silicone adhesive around the sink edge
Position the sink firmly against the underside of the countertop
Support the sink with a jack, braces, or sink clips while the adhesive sets
Install mounting clips or brackets according to the sink and countertop type
Tighten the clips evenly to hold the sink in place
Wipe away excess silicone immediately
Let the adhesive cure fully before removing support
Connect the drain and plumbing after the sink is secured