How do I add a coupon code?

You can apply a coupon code during the initial registration stage when you are entering your credit card information. Look for the "Add Promotion Code" field on the registration page, enter your code, and apply it before completing your sign-up.  

Alternatively, you can add it later from your "Plan & Billing" page. However, please keep in mind that when a code is added after registration, the discount will automatically apply starting with your next billing cycle rather than your current one.