Bonjour Guy,
To add custom fields to the user profile just go to Setup > Templates. Then click on Fit-lters section and make the admin template visible (they're hidden by default).
Click on the user admin template and add any fields you might want.
When you edit a user the added field should be visible.
Under the ProcessProfile module settings, you'll be able to let a user update a custom field or not.
The settings on your second screenshot define what fields should be visible on the list displayed when you click on Access > Users (notice the custom field "Intro" in the screenshot below)
Nicolas
Nicolas's post in Associate a user to a page (a profile page) was marked as the answer