From e-Learning Documentation
Conferences are primarily used for virtual lectures, virtual office hours, and student groups. They can also be used to demonstrate technologies or troubleshoot technology issues online.
Conferences makes it easy to conduct synchronous (real-time) lectures for all of the students in your course. Conferences allows you to broadcast real-time audio, video, demo applications on your desktop, share presentation slides, or demo any online resources. Currently, Canvas integrates with BigBlueButton.
Note: BigBlueButton can accommodate approximately 50 users in a conference at one time. A conference will remain active on Big Blue Button as long as one person is part of the conference room. When the last person leaves, the conference will conclude and all files and chats will be removed.
When would I use Conferences?
Use Conferences to:
Connect with your students for online office hours or special study sessions designed to help them prepare for a test.
Connect with your colleagues for professional development webinars.
Practice presenting online. Students can set up practice presentations in their student Groups.
Invite special guests to your classroom by adding them as a student or observer to your course.
Broadcast a live event or lecture to the students that can't be onsite.
You can also record your conferences so students can view them at a later date. Note: Recordings are automatically deleted 14 days after the conference ends.
How do I use the Conference Index Page?
Conferences are grouped in two parts: New Conferences  and Concluded Conferences . Both always display the name  and the description  of the conference.
Note: Students can only view conferences to which they have been invited.
New Conferences are either ready to start , or in progress  where invited participants can join.
Note: Students cannot join a conference until you have started it.
Once a conference has ended, it will be displayed in Concluded conferences.
Concluded conferences show the date of the conference . Canvas will display the length of the conference . The length of the conference is indicated in hours:minutes (e.g. 0:18 is 18 minutes).
Concluded conferences also shows the state of each individual conference :
- No recording mean the conference was not recorded.
- View [button] means the conference is available for viewing. Note: Recordings are automatically deleted 14 days after the conference ends.
- Preparing video means the conference is being processed.