When you commission Jason Woofenden you are asked to write about your change/addition in the form of a first-person narrative. In this narrative you write as if the change/addition you would like has already been implemented. You write the specifics of what you do and what you see as a result.
Here is an example of a narrative for a new page:
I go to my home page, (or any other page on my site) and I click a link labeled "Contact Us" which is just below the "About Us" link on the left. Then I see a page with a headline "Contact Us" and a form with these fields: "Name", "E-mail", "Comments" and a button "Send". When I click "Send", all information entered is e-mailed to foo@example.com and I see a page with the headline "Thank You" and this paragraph: "Thank you for your interest. We can usually reply within one business day."
After Jason makes the changes, you can verify that they are complete by following the steps in the narrative and making sure you can see everything it describes.