It took some time and efforts to put them on the wall. You might need your own tools to make it easier. 
My cats love it a lot!

But after three months of use, the flat step cannot hold my cat and is broken. Only several brad nails are used to connect the horizontal wood step and vertical wood support. I would suggest to mount the step at a low postion on your wall, or don't mount the step at all for the safety of your cats.