I'm trying to create shelves recessed into a wall, but up off the floor. The only builtin shelf help I can find online consist of a floor to ceiling option, which I don't want. I want the shelving in the wall, up off the floor, under a TV. I've attached a picture similar to what I want. How do I do this? Niches don't allow me to make them deep enough or add shelves, and I can't figure out how to surround a wall cabinet with interior walls. Thanks!