thumbnails for categories and multistep form question

Hi FluentCart-Community,

maybe someone can answer my questions, i didn't get response from support until yet and would need response :)

How can i add thumbnails to my categories?

I need to build a checkout form like this one on https://www.rieger-entsorgung.at/de/shop and for this i would need to show thumbnails on the form. Second questions is how to get a form like this in the link created?
If you test the form from Rieger Entsorgung, you can search for "5020" (Salzburg) at the begining

Thanks for your support and best regards from Salzburg,
Artur