Navigating Between Groups (Instructors / TAs)
Once a group set (like "Weekly Discussion") has been created, Canvas will create a number of groups (like "Weekly Discussion 1" and "Weekly Discussion 2"). Those groups function like a whole separate, somewhat limited Canvas course, with their own roster, their own discussion, files, pages, etc.
To visit the group pages, click People, then the View User Groups button, then pull down the menu by the round gear symbol and choose the blue Visit Group Homepage button:
Another way to get in to one of the groups would be if you have group discussion set up. If you do, click on the discussion, and you'll see something like this:
Click on group icon to show a menu, then click on one of the groups. For students, since they only have access to one group at a time for a particular discussion topic, the will not see that choice, instead, they will be taken directly to the discussion for their own group.
When you visit a group page or a group discussion, you actually leave the course and go to a group site. (Which functions a lot like a course with some limitations). When you're in a group, you can move to another group using the pull-down menu under "Select Group" near the top-left of the page.
Students have more control within groups: they can create pages, upload files, start their own collaborations or conferences, etc. Within a course, generally only teachers and TAs can do those things.
Students can also create their own group within a class, or on their own, not associated with a class. Student-created groups within a class will still be viewable to teachers and TAs for that class.