Layout for new Document

I am creating a new Create Document layout. By default, I see under the Primary Content Source area of the layout, a selection box for where the file is and the file name box. I would like to add to this section of the screen layout.

In Type manager, I can modify the layout and add fields, but they go either in the Attributes section or the Business section.

How do I get these fields into the Primary Content Source section?

Windchill 11.0 m030 CPS16