When sections are linked, you can post an assignment to both sections at once, making material management easier.
You can only link sections of the same class.
Click on the "Courses" menu.
Do not choose a course. Instead, click on "My Courses," which is surprisingly small compared to the rest of your options. It should be located in the top-right of the course menu you opened.
Click the gear icon to the right of the first course you want to link.
Choose "Link Existing Section."