This thing is HEAVY and SOLID. I have three adult cats who needed something to replace their old cat tree. This was definitely an upgrade! I live alone and have MS, so there was no one to help assemble this. But it arrives mostly already assembled; the base is already put together. All you have to do is screw the three (nice, large) perches to the three posts (two shorter and one longer), and then screw the posts to the base. As you can see in the photo, one of my cats was immediately curious about the new tree. They now all three play and sleep on it. They've also discovered the sisal-covered post for scratching their talons. A carpeted cat tree is much nicer than one covered in plush (like my old one was) and well worth the extra cost. Very pleased with my purchase.