Hi OpportunityDoc -
1. Click on the Profiles Tab
2. Click on the Manage Seller Details link in the Seller Details box at the bottom right
Seller Details are not like other profiles in that they are only available for use when you have a template on your listing which is why they are treated a bit differently.
Another note: Currently you are not able to edit an existing seller details profile and save it as a separate SD profile. That functionality is coming soon.
Hope that helps!
Cara