You can set up as many discussion groups as you want by logging on as an administrator and clicking Discuss.
Each discussion group contains the following configuration options:
Full Name - a complete name for the discussion group which will appear as a headline
URL Name - a short name for the discussion group which lets you make a simplified URL people can use to access the discussion group. For example, if your URL name is cats and your web server is running at http://fogbugz.example.com, this discussion group will be located at http://fogbugz.example.com/?cats (notice the question mark).
Tagline - a brief description of the discussion group, which will appear below the headline. May contain HTML tags.
Sidebar - text which will appear in the left-hand sidebar of the discussion group. May contain HTML tags. This can be used to make links to other popular locations, to provide guidelines and FAQs, or for a picture of your cat.
Posting Guidelines - text which will appear right below the message text entry field telling people some basic rules for posting to the discussion group.
Days on Home Page - A number determining how many days worth of topics will be listed on the main page. For busy discussion groups, use a low number like 7 to keep the main page manageable. For new discussion groups, 30 is a good start. Anything older than this number of days will disappear from the main page (although it will still be visible in the archive).
Sort Posts - determines whether FogBugz will automatically attempt to delete posted spam and hold suspicious posts for moderator approval. More about moderation
Open to Public - determines whether you need to be logged onto FogBugz to participate in the discussion group. Of course, your FogBugz server needs to be on a public-facing website on the public Internet.