You can find available JET categories in our Categories Finder tool located in Settings section:
To adjust categories via CSV / XLS file: copy the exact path of a category to your file column "Category path." Keep in mind, JET allows to assign only one category to a product and it has to be the lower level category/ You cannot select any general category. In the example below, you could not select Books & Other Media, only the full path as shown below is allowed to be assigned to a product:
Different categories have different suggested set of attributes, however, for all the categories you can always assign attributes: Attr 119: Color and Attr 50: Size, which allow you to put there any text you want as a value. An example how to use it:
Click here to learn more how to use attributes to create variations on Jet.