There are two places a coupon code can be applied on the website. The first place is inside the shopping cart and the second place is on the checkout page. Please see below.
In the Shopping Cart
Inside of the shopping cart you will see a link next to coupon code that says "add coupon". Please click on that link and a box will open where you can add your code. Please enter the code here and hit the "apply" button.
Once you are in the checkout, you will see a link just above the order total that says "coupon/gift certificate". Please click on that link and a box will appear where you can add a coupon code. Please add your code here and hit the "apply" button.