Email reminder campaign based on certification expiry dates

Hi there,

Looking to create an automation where we have a group of contacts all with a different expiry date coming up for a course certification. We would like to be able to send users reminders leading up to this date and subsequently send them a different reminder if this date has passed. The campaign goal would be if the contact enrols in the product. We are struggling on how to set up a timer based on a custom date field.

Any suggestions would be greatly appreciated.