The Catalog module extends the functionality of Backdrop's taxonomy system. When it is first installed, a vocabulary named "Product Catalog" is created with the following settings:
- Multiple inheritances -- Terms may be in more than one place in the hierarchy.
- Multiple selections -- Nodes may be in more than one category in the Product Catalog.
- Not required -- Product type nodes are not required to be in the catalog.
- No free tagging -- Categories must be specifically created before being used.
- Node types: product
Any of these properties may be changed as with any other Backdrop CMS vocabulary by browsing to Structure » Taxonomy (admin/structure/taxonomy) and then selecting the edit vocabulary link. If other modules that define product-like nodes are enabled, those node types should be allowed in the vocabulary. When a product class is created, the new node type is automatically added to the Product Catalog.
The Catalog settings page at Administration » Store » Configuration » Catalog (admin/store/settings/catalog) lets you change which vocabulary is used as the product catalog. There is also a text field to set the URL that links to the main catalog page. The checkboxes contain various display settings for the catalog block and pages. The choice for the number of grid columns should be based on your theme.
To read more about adding categories to your product catalog, check out the following page:
http://www.ubercart.org/docs/user/10964/building_product_catalog