Well before we could even put them up two of our kitties had to check them out first.  
Definitely a good idea to have two people to put them up.  One to hold and one to drill.  They r very well built once put together which wasn’t too difficult at all and pretty good deal price wise too.  
I just wish the bottom shelf was a lil bigger for a couple of our chonkers.  Kitties love height and to b left alone sometimes so I’m hoping these will work for them.  They love to hang out in this bedroom during the day.   
It’s their kitty romper room.  The cat tree and window seat were from Wayfair too.