I built my shelves and brackets with plywood leftover ... You can use: Mark a level line on the wall and drive screws through the cleat into the wall. The shelf shown was attached to concrete ...

Cardboard may be one of the easiest materials to recycle, but that doesn't mean you shouldn't try repurposing it. Here's one ...

It took us a couple of hours to build each shelf ... wood screws through the shelf’s pilot holes and into the wall cleat.