Paint the table top with two coats of the lightest color you plan to use for your squares. It is much easier to paint darker squares on light than it is to paint light over dark.
Use a pencil and a long straight edge, such as a yard stick, to draw the squares on the light paint after it dries. It can become confusing trying to remember which squares get which color. Make it easier now by painting a tiny dot of the correct paint color in the center of each square. Those that will remain the light paint color do not require a dot.
Use masking tape to outline the squares you will paint a darker color. This will help your squares have a sharp edge. If you plan to use more than two colors, paint all the squares of one color first. Allow to dry, then repeat with other colors. Allow all paint to dry.
Protect the paint job with a top coat of sealant.