Changing message_payload on wpMandrill

Hi there,

I have Mandrill installed on my wp site I'm having trouble adding and editing *tags in mandrill, that would call specific fields. For example, username, password, email, message, etc. I don't know where to add the tags.

Ultimately, I would like to replace transactional emails with Mandrill for messages like New User, Profile Submission, Profile Published, Forgot Pass, New Message. While they're all using the same Mandrill template, their messages and content have to be different but i dont know how to edit.