EMPLOYEEI’m confident0Hi Nikki,
I think someone may already have answered your question on the site, but I'll answer it here in case anyone else is wondering.
There are (currently) two ways to submit stories/other works to groups. This assumes you already belong to the group you want to submit to, of course, and that the group in question allows submissions (some may not).
To submit an existing work:
(1) Go to the story you want to submit.
(2) Click the Actions menu on that story, and choose the "Add to or remove from group" option. You'll be able to toggle group membership for that work directly there.
To post a new work directly to a group:
(1) Go to the Read page for the group in question.
(2) Click the "Submit a new work" button on the Read page.
(3) You'll be presented with the writing form, but it will be tailored to the group you're submitting to. Fill out your first chapter, and hit submit.
Voila! Hope that helps. :)
-nick / protagonize