The only assembly was applying the fuzzy stair pads (stickers).  These stairs are a must-have for me- my two small dogs sleep with me and can't get down on their own.  The height is perfect to the top of my mattress, but my bed is taller.  The stairs are plenty sturdy for my 6 pounders, but tend to move around a bit on the wood floor.  I am going to place a rug underneath so they stay put.