Not the easiest instructions to follow, but these bunk beds were very impressive in their engineering.  Every hole was in the exact right spot (no having to force screws or bolts at an angle... and theres a LOT of screws and bolts).  90 percent is wood (not MDF).  Ours arrived with the exact number of bolts and screws.  Take your time with the first two steps of the instructions.  Im fairly proficient at this sort of thing and I had to re-do a couple of steps to make sure I had it right.  Switching the stairs to the other side seems possible, but would be very difficult.  Overall, Im impressed.  Definitely worth at least what we paid.