This cat tree was easy to set up using the instructions.. though, if you're alone as I was - you'll need a ladder or to jump up on your counter (like I did) for the top part - that's where the heavy duty tension spring is located. Only took me about ten minutes to get it all put together, sturdy and set in place. And I'm actually re-using the box as an agility course for my cat since there ws a pre-cut hole, I pour a couple treats in it and my cat reaches in to get them out or just crawls right into the box to get them haha :) 
My cat has been on it daily since it arrived - he loves it!