i would like to build a similar wall unit for fabric storage. What I need to know is what do you use under the bottom shelf to raise it up off the floor? Is it a 2x4 frame? And do I need to put a back on it, or can I use the existing wall. If existing, then how do I attach it to the wall?

I'm interested in the wall unit too and would like to look into making them for my Lego room. I'm guessing the wood boards were bought then a table saw was used to cut the grooves and painted over with a semi-gloss paint?