It’s one big unit all connected together. It’s is held in by screws just past the surface. I thought because of the size it would need a back support on the bottom. But so far it doesn’t.
By Sophia Halifax
I installed a support across the bottom at the same height as the lower front opening. That way you just slide in and it is fully supported, then put 2 screws in rear to the support brace to lock it in place. Place screws where you can easily remove in case you ever want or need to remove.
By Abel Owen
The unit attaches to the inside of the holes. Mine is secure and works perfectly
By Matt Isaiah