The Amazon category dropdown can be seen in the Amazon section in the product editor next to the Sub-Category field:



 

It is important to note that the values in this dropdown don’t get pushed to Amazon. It is used to help find the exact browse node ID to put in the Sub-Category field. Once a Category is chosen from the dropdown, it will refine the dropdown that says “Select a Category first” like so:



 

The Sub-Category Nodes field to the left of that dropdown can be used to refine the list more by inputting keywords:



 

Once you find the exact browse node from the dropdown and select it, the Sub-Category field will populate with the Browse Node ID:



 

This is the only method you can do to find the browse node ID within SureDone. Other ways that you can find the browse node IDs is either by downloading the Browse Tree Guide from Amazon at this link or going to www.isoldwhat.com/amazon.