After selecting the products you intend to purchase, you will find all items in the Cart. To redeem the coupon you will need to click on Checkout, as shown below:
In the appropriate field (circled in green below), you can enter the coupon you have, being careful of any spaces before or after the code; then click on Apply.
The code is valid if it is correctly applied to the total value of your order, as shown on the right side of the page, where you can see the Discount line, the discount code you entered, and the wording Applied.
Complete the order by proceeding with payment.
The terms and conditions of use depend on the individual code, which may not be combinable with other promotional initiatives or not applicable to products already on promotion. For further information regarding your code, contact our Support Team.