I assembled this by myself and I made a few errors in hammering the nails into the back. The instructions for assembly were quite tedious. I didn't like how it wasn't clear where to hammer the piece of cardboard onto the back so I hammered a few nails right through it on accident. I am also not very handy so that could be the problem.  Luckily the nails went through on the inside of the bookcase where not easily visible. For the price, it wasn't worth it to get another one. Its also a lot smaller than I had imagined but it will work for now!