Sadly cats have zero interest in this cat tree. 
Second tree I bought they love ( different brand )
I think big missing piece is some kind of Velcro adhesive small carpet type of padding for shelves - steps - it is too slippery for cats - polished treated wood. The other cat tree has them and they are loving it. Sadly not worth returning for 24 credit after paying 45 for return shipping after paying 113 .