To create a new recipe category, first, go to the Categories catalog. You will then see the categories of each type separated by tab. Note that if you do not have a category of a given type, a tab will not yet appear for that type..
To add the new category, click the + next to the Categories header. This will direct you to a page where you can name a new category and pick the "item type" for the category. If you want to use the tags to categorize recipes, choose the "recipe" item type. You can also pick options like "ingredient", "menu", "menuItem", "vendorItem", or "purchaseOrder".
Once you've created a new category, you can add values by pressing the "+" next to "Category Values" and typing in new values. Now any recipe can be tagged with these values.
To learn how to tag a recipe, check out this article (How do I assign a category to a recipe?).