I had been looking for steps for my pup.  He has short legs and seems to need a boost up especially in the car. I ordered one of each size on the steps and found them very easy to put the foam 3rd step into the cloth form. The steps came with two steps already inserted which helped.  My pup is learning to use the steps for getting up on the couch and also into the car. They were both a fun learning experience for my pup.  I am very pleased with my purchase. Thank you.