If you cannot find your class under the My Courses/Uncompleted Courses tab (scroll down if needed), it may be under the “Completed Courses” tab. Courses are ordered by name.
To “Complete” a course and generate your certificate, click on the “Complete Lesson” buttons on each lesson page or the “Mark As Complete” button on the “My Courses/Uncompleted Courses” page. More help can be found here.