Be sure the classes you have added to your cart are in the scope of your coupon code.
For example, the coupon will state that it only applies to on-demand courses or a specific course.
Once checkout is complete you will be taken to a 'Thank you' page. Please wait 30 seconds for the system to enroll you into the course. After 30 seconds, check 'My Courses'. If you do not see your course, please hit the refresh button. It should not take longer than a minute for your courses to appear.