Contrary to some posts, I found this very easy to assemble.  Lay out all the pieces in groups and pay attention to the bolt tops...I did not and had to change out three of four on the bottom platform halfway through the assembly. No worries...did not have to disassemble,  just swapped them out. You definitely need to cinch down the poles by hand after you bolt them in. I found them wobbly as noted in other reviews.  When I turned them like I was screwing them in by hand, the posts became more solid and stable and the whole tree become completely stable. Also pay attention to the posts that have threaded bolts already in place those are for the top level platforms with the toys attached. The pictures are helpful. This took me about 30-45 min to put together by myself.  I would highly recommend this "CORNER" cat tree!