Currently, Tern's email integration is meant for individual or small group emails. It's not a good fit for sending bulk marketing communications at this time.
Bulk sending requires a lot of work to prevent emails from being flagged as spam. Adding support for marketing emails / bulk sending is on our radar and is something we plan to add in the future!
Email campaigns are currently available to a limited group of users as we continue to refine the experience. We plan to expand access in the future. Tern's email integration is designed for individual or small group emails — for large-scale marketing sends, we recommend using a dedicated email marketing platform.