How do I track which messages the clicks came from?

If you need to track the source of the clicks for the same link/URL (e.g., broadcast VS follow-up message), you just need to create separate trackable links for each source.

For example:

Trackable Link 1

— Name: Blog on Broadcast010

— Tag: blogbroadcast010

— Description: Blog link on Broadcast 010, subject: Hello!, sent 20210101

— Web page to redirect to: https://example.com/blog

Trackable Link 2

— Name: Blog on Active Members Message 001

— Tag: blogActiveMembersM001

— Description: Blog link on Active Members Message 001

— Web page to redirect to: https://example.com/blog