Easy to put together... took 20 minutes! Reviews on here about problems, are nonsense! Very incompetent people who try to do diy should stick to burning toast! 
Will add a photo when room is finished as they have been assembled ready to affix to wall once repainted the room. With regards to attaching to walls, use your own experience to what screws and fixings to use, there are many wall types out there, and if you don’t know what to use for your wall you should not be doing DIY!