Mark a line at the half-way point and cut your 8' board in half.
Take those two pieces and cut them in half again.
Your next cut will be halfway across two of the boards. Find the center point. Trace another board (standing up - as pictured.) You will do this for two pieces.
Cut those two boards that you just traced. You can use a circular saw for the longer pieces and a jigsaw for the small bit left over.
They should interlock with each other now. You may need to give them a little tap with a hammer. If it's any more than that, you may need to adjust your cut. After that, you'll add the side and top of the boxes. You will only have one side and no bottom, because the coop will cover both of those.
Because of how we built the coop, there are some cutouts that will be necessary to place the nesting boxes right up against the wall. (You don't want to lose any valuable eggs!) Mark those and get out the jigsaw.
Put the nesting box where you want it, trace it, then predrill holes to the outside.
Once you're outside, use some wood screws to attach the nesting boxes to the coop
Using the same method, predrill the side that the lip will attach to.
Screw it in place. Attaching to the outside wall, middle brace and outside brace will be enough screws to keep it in place.
We used Primer/Sealer/Stainbocker. It's mildew resistant and will make keeping your coop your coop clean.