Here's one enclosure set up on sawhorses for a test fit. The braces inside each side panel add to the stability of the unglued enclsoure during this step. Use the yardstick to make pencil marks along both edges of the front panel at the following distances from the top: 2" 10", 18", 26", and 34". These marks indicate the location of the 1-1/2" #4d finishing nails you will use to align and secure the panels. (OK, I'll admit it - I recessed the drivers because I have a router and it' easy to do, but it isn't necessary).