Your course team may have decided to encourage some online discussion of your learning. If so, you'll most likely have access to some discussion boards within Brightspace.
You can find these by selecting 'Communications' from your navbar and choosing 'Discussions'. You may then see some discussion forums - which are simply categories and the location of the discussion itself - and the discussion topics that belong to them.
The video below will show you how to find this area, how to subscribe to a discussion and how to post a thread.