STEP 1 ™ Carefully measure the thickness of the sink at the lip and build a support 4 AT X structure using larger lumber and secure to the inside of the cabinet that the top of the support structure can accommodate the thickness of the sink under the counter. KINGSTON CREATION STEP 2 Add a thin bead of silicone on the top surface of the wood support structure and place sink on top, it may be necessary to shim it to obtain a tight gap between the sink and the counter.