Pay attention to all of the instructions before you start building. I put one piece on backwards. There was a warning, but it was on the bottom of the page after the step instructions so I missed it until after. Otherwise, relatively easy to put together by myself. A little heavybulky to move alone but I managed. Kitten loves playing and running around it. Our older cat thinks its just ok so far. Both have used the litter box in the cabinet. I put a folded litter mat under the litter box for easier cleaning, and installed a small Fresh Wave deodorizer. House guests were surprised when we told them there was a litter box in there!