Ho to add a Tag CATEGORY (not a tag, but a category)

The manual explains how to add a tag or rename a category but NOT how to add a new category.  Initially Rekordbox has four categories but I'm sure I've seen screenshots of Lexicon (which exports to Rekordbox) with six or more catagories.  How can I add a new catagory or is it just not possible.  I Googled this and it's been asked several times but answers just explain how to add a tag - which is simple and is not what is being asked for