Log into or create:
Coke Rewards Account http://www.coke.com/offers
Scroll down to:
"Drink in More Movie Perks with Coke"
1 Product/Cap code
If you don't have a code:
From your phone/tablet, go to https://us.coca-cola.com/offers/
(the offer only shows up on the mobile page, not the computer one, plus only mobile lets you do the scan thing)
Log into your Coke account
Find the offer, then click on the sip and scan button (red dot) thing
Load the photo of the sip and scan onto your computer or another phone. Others were kind enough to upload them. Here Is one example:
Take a fairly close photo of that sip and scan picture.
Ends 9/24/18. Limit one offer per person. Must be first time enrollment. A credit card is required for this offer. Membership will automatically renew.
See T&Cs for all details.