I just discovered that with the auto-renewing subscription for the 20 hour course, we have to go through the FRONT END of the website, or else it will mess up the auto-renew.
You cannot go through the Admin area and enroll user or else the auto-renew function won't work.
So, if we are enrolling someone in a free course, you need to create a coupon code and then provide it to the user and have them go through the buy process.
Send the user the link to the buy page and then just let them know to click "Apply Coupon" at checkout to get their discount/ free course.
Also make sure to put the limit to number of times coupon can be used, this is done when creating the coupon code from the Admin area of Thinkific, this avoids someone being able to share the code with another user.