I have been looking at photos of closet organizers and thinking of building a system. I am wondering how people mount end boards to the walls (sideways, generally looks like 2X12's) and make them stable when they are in the middle of a wall. Some of the photos don't look like they have back boards to attach them to. How do you keep the boards stable standing with their narrow side against the walls? How do you attach them? Thanks for ideas.