When you create/edit a product, you will see field called “Tag list”. Enter a comma separated list of categories into this field, and they will be used to group items together when listing items in the store page. This makes it easy for users to find products that interest them.
For example, let’s say you are selling T-shirts. You could tag a shirt with a list like: “T-shirt, blue, large”, and another shirt with “T-shirt, blue, small”. In the store, it would list categories for T-shirt, blue, large, and small, with the number of items in each of those categories. When a user clicked on the Large category, only those items tagged with large will be displayed.