First of all, I had to open up the tabs because they were a bit too small for the slots to fit through ;) . I did this by use of my hobby knief so the problem was not hard to fix. I decided to add hardwood floors on the first level and bought a nice sheet of this flooring at hobby lobby for $4.99 not on sale. It has a paper back and is unfinished so that I can stain it the color of my choice. I glued it down with tacky glued and let it dry as I started assembling the back foundation wall and side walls pictured below. I used Quick Grip Glue (it dries faster) & Probond wood glue (because it works best in the long run).Complements of My Mini Shop