so I built this locker shelf.
Step 1: Materials
nail/screw/staple gun (just something to attach the pieces of wood together)
Step 2: Measure and cut
The top shelf is the same width as the inside of the locker.
The two pieces below the top are the width minus the thickness of the two side pieces.
Cut the skinny piece of wood as shown.
Cut the side pieces to the length of your locker but to the height of your choosing.
Step 3: The middle shelf
mount it to the side piece at the height of your choice.