Once you've created a Category (collection) in your BigCommerce account, you can import it into Shogun to add custom content.
How to Edit a Category Page in Shogun
The process is simple. Click on the "Create New Page" button at the top of the Shogun editor. On the Create New Page screen, click on the "Collection Page" button at the bottom. Then, select which of your Categories you'd like to import.
Your selected collection page will then open in the Shogun editor, and you can begin adding your custom content.
You will see 1 drop zones with which you can make additions of new elements above your theme template.
The products displayed on Category page are controlled by your theme's template and the BigCommerce catalog. Shogun can be used to add dynamic content into the top region of the page.
"There are no products listed under this category"
This is normal. Your products will be displayed correctly on the live page, there is nothing to worry about!