I started with the base using a piece of plywood roughly 12″ wide by 21″ long. Then I mounted a runner underneath to fit the miter slot of my table saw. Locate the runner so you can trim the edge of the base to create a clean reference edge for locating the clamping square. The last step is to attach the clamping square to the base. A drafting triangle registered against the plate of the blade positions the clamping square at the correct angle. Now, perfect, gap-free miters are guaranteed with this simple sled.