I live in OH and will be helping my CA son build a basement bathroom in his rental home in KS. The floor is concrete. I believe that the drain is roughed-in, in a corner of interior studded walls, no drywall yet, and I recall that the concrete is a little rough, and the floor may not be level. How do I install a neo-angle fiberglass shower unit (base, then walls)? Thank you, Roger Storm

