Three automations worth setting up first
These three cover the moments a loyalty program should react to on its own: a contact earns enough to claim something, hits a purchase milestone, or moves up a tier. Each one starts from a template, so none of them needs a blank canvas.
Design the email first, under Marketing → Automated emails, and publish it. An email that isn't published can't be selected in an automation.
1. Reward unlocked
Go to Automation → New automation, pick Reward unlocked and click Next. It asks for the number of loyalty points and the email.
It emails a contact 10 minutes after a transaction takes their balance from below that number to that number or more, which is the moment they're most likely to come in and spend it. Re-enrollment is already on, so a contact who spends their points and earns them back hears about it again.
Example: "You've unlocked a free coffee. Redeem it on your next visit."
2. A purchase milestone
Automation → New automation → Thank your loyal contacts for their 10th purchase.
The count isn't fixed at ten, despite the name. You set the number when you create the automation, and the email goes out 10 minutes after the contact receives points for that number of times. Pick whatever counts as loyal in your business.
Example: "That's your tenth visit. Thank you, here's something on us."
3. Tier reached
Automation → New automation → Tier reached, which asks which tier it's for.
This template doesn't add the email for you. In the editor, click the + in the flow and add an Automated email action, pick the email and click Update. Build one automation per tier if the messages differ a lot, or one automation with an If/Then branching on the tier. Either way, a contact hears about the perks at the moment they earn them rather than the next time they happen to look.
Example: "You've reached Gold. Here's what comes with it."
Two settings worth checking on all three
Open the Settings tab in the editor before you activate.
Re-enrollment decides whether the same contact can go through more than once. It's on for Reward unlocked and off for the other two. On a tier automation, off means a contact who drops out of the tier and reaches it again doesn't get the email a second time.
Execution window decides when the actions are allowed to run. Leave it on Direct and a contact who crosses a threshold at three in the morning gets emailed at three in the morning.
Where to read more
Automated emails: setting one up for any trigger walks through designing the email and building the flow. How to build an automation is the fuller reference, and Automation triggers lists everything else that can start one.