The additional 20% PRO discount is applied directly to the courses, you don't have to do anything!
As it is additional, you can use another promotion or discount code in your order. Then, in your shopping cart, you will see the final price of your order and the information on each discount in a detailed way.
Please note that the PRO discount is not added to other discount percentages, but rather the PRO discount is applied to the current course price.
Please remember that the PRO discount is only valid on the web and it applies to individual courses that you buy to take from your profile, it will not be applied on Course Bundles or Gifts.