Icons for Row Layout

Thanks for this wonderful plugin, just figuring my way out with Gutenberg. Please check the page I have created a row layout, would like add new icons from the web. Have three icons, one for new cars, the other for used car the third for parts and accessories. The one that come with Stackable are not doing the trick. Is there a way to import other icons.

Also is there a way to list one category per column.

The page I need help with: [log in to see the link]