Ron, just below the top of the Property Sheet there will be a 'Selection type: ####'

What does this say?
Form
Section
Label
Text Box

There will then be a dropdown just below it that which has the name of the object you have currently selected.

This needs to be 'Form'
You can also click where the rulers meet in the top left hand corner of the Form, a small black square will show, and now you can set the Record Source of the Form to a Table/Query.

Now you mentioned "I do not get a list of all the fields in that form", this would be the case where you have a Control selected like a Text Box and then you would be setting the 'Control Source' to a Field in your Table/Query that you have but the Form would need it's Record Source first to allow the Form to know what Fields are available for that to use.

Alex