Easy to put together. Like other have mentioned, the pilot holes in the back of the units werent central, so we made our own, but this was very easy. What wasnt easy was the hanging! Lol. Took us 2 attempts to get the shelves straight. We didnt make any additional holes in the wall, but rather adjusted the hanging hooks on the back. The sticky pads for the mounting were a great idea, but we just couldnt get them to work. Bit of a ball-ache to hang, but was well worth it for the finished effect -) Love them mounted 3