I don't think you can view Hosta Catalogs on the Plant Step Flower program like you can the daylily Catalogs. I was not able to find a way.
Pulled this from the site:
"Create Full Color Catalog for your Daylilies, Hostas, Roses, Irises and Perennials. View your daylily catalog on the Plantstep website."
To me that indicates that you can create a Hosta Catalog, but you can only view the daylily catalogs on the Website.
I could be wrong, but that is what it looks like to me.
There may be another to view the catalogs other than the plant step website, but I don't know of one.