The Discussbot allows you to integrate your Forum discussions with your content.  At the bottom of your content items it can include a link to the discussion about each article and optionally include a subset of the running commentary.

Once you have the mambot (or plugin in Joomla 1.5 speak) installed you will need to publish it.  This is no different than any other bot, module or component.  Before the bot gets loaded you have to enable it in your FireBoard Config.  Once it's enabled and published you're almost ready to see it on your Joomla! website.  

There are two ways to add the discussbot to your articles, by adding tags to your content or forget the tags and use the "Auto" features.  If you have a site where only a small portion of articles are discussed in your forums, you may be better off using tags and only add them as required.