How do I mark my letters "prepared"?

If you log in to your Vote Forward account, and go to your dashboard, you can use the gray "Mark prepared" button to mark a bundle of your letters "prepared" at once. This will move the bundle to the "Prepared" column. 

To mark individual letters as "Prepared" use the blue right-facing arrow to the right of "View 20/20 unprepared letters" and then use the right-facing arrow to the right of an individual letter to move to the "Prepared" column.