Categories in Concept3D are containers for sub-categories and locations. They are used to organize the map sidebar and to group related locations together within a category. Sub-categories can be used for further division and organization of locations. Categories are found within the map sidebar under the "Locations" section.
Vendor Documentation: https://help.concept3d.com/hc/en-us/articles/360023798134-Creating-A-New-Category-