How do the newsletter shortcodes work?

Perhaps I'm just overlooking this, but I can't seem to figure out how the enewsletter shortcodes actually work. Is there documentation that I'm not seeing?

I've put in the page id for a page that I'd like to use for an "unsubscribe" page, and then I'm lost. Putting the shortcode on that page doesn't seem to do anything.

Thanks!

Danita