Complex build, but very well labelled and good instructions.
Instructions similar to IKEA, but with all the flat-packed pieces actually numbered discreetly on each piece of wood with a small removable sticker - always in places you won't see anyway (a huge benefit in a complex build like the bunk beds I purchased).
Definitely more than a 3-hour build (even for an experienced flat-pack constuctor with power tools), but sturdy and well designed.
My only complaint being that it could do with some diagonal bracing at the base because it's extremely difficult to move once constucted, especially on a carpet, without straining the joints of the end sections. Not a problem once its in place, but it is diffcult to move around without damaging it (like a lot of flat-pack furniture).