Cut the circles for the two 1/4 inch sheets that are clamped to each other. Use a 4 inch circular saw. Secure the boards and take your time to safely cut each hole. Hole saws are dangerous so please read the directions on how to safely use the hole saws. The 18 volt battery powered drill will work, but it is nice to use an electric drill because they have more power to get all 42 holes done.