Once you pick what subscription you'd like to sign up for via the following links...
A window will pop up where you need to enter in your subscription information. The window looks like this:
To enter in your coupon code, you'll want to click on the yellow highlighted area (see screenshot below)
From there, you will enter in your coupon code and then click on the red arrow:
Once the coupon code has been added to the order, you will want to click on "Edit Order" to finish filling out your address information.
Please reach out to firstname.lastname@example.org if you have any additional questions.