Sending a unique timer for a user after an order (maybe as part of a drip campaign, or in a receipt) requires your email software to be able to include the order number in the MotionMail timer URL.

Please see this article for more information on setting up this feature in the most straighforward way:
How do I make a timer start when the user opens an email?

Note that since MotionMail does not know about the promotion until the first time the URL is loaded, the end of the countdown may not exactly match a discount code or promotion that is set within the e-commerce software. We recommend to either provide some grace period on the end date (say it is 48 hours but actually set the discount to expire after 72 hours), or use one of two other MotionMail options to get the time set exactly.

Options to set the end time seen by the user exactly include: