Full Instructions http://cavycages.com/forum/showthread.php?t=8067
Use mending plates and screws to secure the shelving (or cubes) to the frame. The screw allow you to easily remove the sides if it's ever needed. Notice how the bar on the shelving protects the wood and coroplast from chewing. I assume that eventually I will need to change the coroplast and since the bar of the shelving overlaps it the easiest way to replace it will be to take the sides off. That's where the use of screws will come in handy/