Templates are a subset of Categories. The same information, but just a shorter list, and you might not have any.
Template items have to be added from the Category screen.
You can filter this list of items down by selecting a category. This list only shows categories for which there are templates; this is different from that on the Categories screen which shows all categories.
Then click on the blue Edit button to open the detail screen. This is the same screen as you would edit a template from the Cateogires screen, but the header title displays differently.