These instructions make a corner by butting one board up against the other. After determining your dimensions and reading through all instructions, purchase materials. Use scraps and leftovers when possible. Bring dimensions to the store with you. Some stores will cut wood to length, saving a step for you.
Splinters Sand the boards.
Use a sander or sand by hand. If sanding by hand, here's a tip. This will make the sanding go faster and will be easier on your hands. Make Square Frame Make square frame by putting the boards together as before. Fit the boards together so that the frame is as deep as possible.