When you turn in your last project assignment, that will be a "final revisions" assignment. That means reading through your project again, page by page, with fresh eyes, looking for anything you want to add, remove, update, edit, etc. If you have pending revisions from the previous assignment, make sure you complete those also.
FILL IN THE FORM and DO THE DECLARATION. Then, after you have submitted the form, you can do the Gradebook Declaration for the Project assignment in Canvas. CONGRATULATIONS on being done with your project! :-)