Installing a laminate countertop can be completed yourself with a few tools, and you can follow these simple instructions to replace a countertop and install a new sink as well. Remove the Sink Shut off the water supply by turning off the water valve underneath the sink. Take out the bathroom sink. Remove any objects off the countertops. Disconnect the faucet from the water lines by unscrewing the nut underneath the sink that attaches the sink to the waterlines and it will be near the top of the lines. Undo...