When you create products and assign them to categories, the way those products display on your storefront category pages depends on your theme settings. Every theme in our Theme Store app is a bit different, but they all share elements in common.
To edit how Products display on your Category pages, go to your Site Designer using the Navigation Menu on the left side of your Dashbaord, and view your site's Homepage. From this point, choose "Category" from the Page: Home dropdown at the top center of the page. Hover over the section you wish to edit and click the "Edit" or "Edit Template" icon that appears at the left side of the section. Specific options available vary by theme.