After you've completed your Instructable, you submit it into the competition by sharing it with the Ponoko SketchUp
account. Here's how:
1) Click the "share" tab and the "collaborate" tab while you're in the "edit" section of your Instructable.
2) Click the check box to "enable collaboration".
3) Click the “+ add/remove collaborators” link.
4) Type in the member name: "Ponoko SketchUp", then click the "add" button.
When you can see "Ponoko SketchUp" appear as a "Collaborating Member", you're done!
(Note: You do not need to publish your Instructable to enter the competition. But if it's worthy, why not?!)