You can add an instance/class to a course in two ways. First, from the Edit Course Page, you can use the “Add instance/class to this course” button to create and add a new instance/class.

Alternatively, you can do it from the Course Listing Page by using the action icon “Add Class/Instance” to directly add an instance/class to the course without entering the Edit Course Page. Both methods allow you to easily expand and manage instances/classes for the existing course.