Most people will post a topic with the story title, their pen name on the archive, the fandom or subdomain where it can be found, and a link to the story. I've also seen people put in a summary to let potential readers know a bit about the story. Take a look at some of the other threads posted by authors. The only requirement is that the story be posted here at AFF (even if it's also elsewhere) and that any link be to the story on AFF.
You do need to post the story in the archive, though. These forums are not the place to publish.
It's actually a great way to let people know you're posting, especially if you're new. It goes hand in hand with making a review reply thread, so you can respond to reviews and get a chance to chat with readers.
