With the Upsell Script example, offers are presented in the order found in the upsell path. Meaning when you complete the first offer in the upsell path, your next stop is offer #2 in that order.
What does the Generate Upsell Script do?
This builds the link to the next offer (http://#domain#com/?uo=starting_offer_id&c=next_offers_creative_id)
Drops an impression pixel so we know they viewed the upsell.
Pulls the image creative from the assigned upsell image.
If "Next Offer" is clicked we store that info, so if they click the same link from their email, then we would bypass the "Skipped" Upsell offer. You can only go up, in the upsell path, not down.