the bed. Ken did all the cutting for me.
I stained my wood pieces before assembling so I wouldn't need to worry about any dripping on the vertical pieces.
The design was very simple. I used a 1 x 12 board for the top and bottom. Ken cut it to 24". I used a 1 x 4 board for the back and sides. I made my side pieces 10 1/2 inches long so they were set back a little. Then the back piece was cut to fit between the sides. Originally I cut it down to 22 1/2 inches but I had to trim it down a little to fit.
I decided I would mount the shelf using a french cleat, that way there would be minimal holes put in the wall. For the french cleat I used a 2 x 4 piece of wood also left over from the bed.
I would recommend attaching the top of the cleat to the back board before assembling everything else. Drill your screws in through the back into the cleat. Then attach the sides using wood glue and wood screws to form the sides of the box. Next attach the top of the shelf lining the back edge up with the french cleat. The cleat should be recessed into the box.
Attach the bottom next and you're almost done.
Attach the bottom piece of the cleat to the wall securely at a comfortable height. I chose to hang mine at mattress height. You should now be able to hang the finished shelf on the cleat.
In all fairness, I was trying to reproduce a french cleat based on memory. I forgot to use the power of the internet and didn't recess my cleat which caused the drawer to tip forward. I used two 3" L-brackets beneath the shelf to add additional support. Had I assembled my cleat correctly they shouldn't have been needed.