This item was a breeze to put together. The four screws to hold the top bed on are already a little driven into the top bed, so all you need is a driver with a Phillips head to finish putting the top bed onto the wood base, which appears to be solid wood. other than that the item is already built for you. it is very sturdy--there was a slight disagreement between cats last night as to which should occupy the top bed, and the tree did not rock or move at all during the kitty-altercation. I cut a small fleece blanket into smaller pieces to make it more cushy for the cats, although I had to wait for them to vacate the beds to put those blankets in there, so clearly, it was fine as is as well. This is one of the best cat trees I have experienced, although it is just beds and a scratching post, no fancy other stuff like boxes, ladders, and hammocks, etc.