Sand your countertop with 200-grit sandpaper. Sand off all shiny spots so that the paint will be able to stick.
Wipe down the sanded countertops with a moist cloth to remove any residue left from sanding.
Paint your desired color with a foam roller. Let the paint dry overnight.
Apply second coat of paint, if needed, and let it dry overnight.
Paint water-based polyurethane over the countertops with foam roller. Let it dry overnight.
Apply second coat of polyurethane and let it dry overnight.