You can find out more about attributes in this article [it can be used for any attributes]: How to add listing attributes - HivePress Help Center. In short, the page area refers to the dedicated, full page for a listing, vendor, or request. The block area refers to how that listing, vendor, or request is displayed as a block within a page that contains multiple items.
If you have vendor categories and are using direct vendor registration, after signing in, the next step should be the Complete Profile screen, where vendors can select their category. Regarding multiple categories, you can take a look at this topic:
Please let me know if you need further assistance.