What are Product Concepts?

The second (2nd) tab in the "Create/Edit" product page is the "Concepts" tab. Here you may assign your product to any of your concepts.

There are three (3) checkboxes for each of your listed concepts. You may choose to make a product "active", a "key item", or both by enabling the 1st checkbox shown before the name of the concept (This will auto-enable both the "active" and "key item" checkboxes).