From Shopnix Help
Cataloging your products properly will help your shoppers find the product they want easily and quickly. Lets take the book store example from the Inventory page and explain how to create the catalog.
Below is the catalog for reference again.
First you have to create the topmost elements in the catalog - we refer to them as Product Types
Creating a new Product Type
Voila! Your first product type has been created.
*When you create a free store you get a few default types called as "Women" & "Men".
Delete them before you start building your catalog.
Repeat the same process and create the "Fiction" and "Health" Product Types.
Creating Product Categories
Next you need to create the entries "Medical" & "Law" under the "Academic" Product type. We refer to these as "Categories" in Shopnix.