Since you've never collabed before, Alyss:

Generally people who are collabing just write something like [b]"Collab between ___ and ___"[/b] at the top of their post. Also, people can switch partners/groups if the IC situation calls for it. They don't really need to report who is with who... unless you want them to for personal reference, of course :)

EDIT: I'm open for anyone to collab with me if they want. For now I'll just work on a solo post, but let me know if you'd like to try!