If you are on a mobile device you can add your discount code after you click the 'Checkout' button on the cart page. Once you are at the checkout process press the button labelled 'Order detail & discount' at the top of the page. This also applies to gift cards. If you are on a computer or laptop you can simply add your discount code after you click the 'Checkout' button on the cart page. On the right hand side you will see your order summary and a box for your discount code. This also applies to gift cards.