To introduce users to your discussion, or provide key background information, you can write a topic info section, which will appear in the ‘Info / Stats / Topology’ window. This window appears when users first visit a discussion, and can be pulled up at any time from under the discussion menu (see: Statistics and the Infographic).
To write or edit your topic info, go to the discussion menu (click on the three horizontal bars at the top-left of the screen), and select ‘Discussion Settings’. In the ‘Background’ field, write your topic info. Note that you can add links as you would to a claim (see: Adding a Link).