How do I add a field in the Item Catalog details page?

Summary

I need to add a field in the Item Details of the Item Catalogs page

Content

Navigation: My Client Groups -> Profiles -> Item Catalogs -> Item Catalog Name -> Edit one of the items within the Item Catalog and it brings you to the screen i have posted in the Image section below titled Content Item 3.

Is there a way to add a Flexfield to that region? Under Item Details there are already 4 fields showing and I would like to add a couple more. Is this possible in Manage Descriptive Flexfields?

There is a Content Items section in Manage DFFs but I would not know how to get it showing on that page specifically.