Hello Salty. First, add the shirt to your cart and start the checkout process. You will arrive at the page to enter your shipping and billing information. On the right-hand side of this page (above the order total), there will be an entry-field that says "Gift card or discount code." This is where you will enter your unique discount code for the Moments of Triumph t-shirt. Once you enter this code and hit the Apply button, you will see the normal price for the shirt and can continue with the checkout process. I hope this helps you!