You have a promo code? Congrats! Let's go get that discount applied to your purchase. It's very easy.
Select the products you want to buy, and go to the checkout page. Fill in your complete and correct invoicing and shipment data. Remember that to avoid delivery issues, it's best to use a local mobile phone number, as some carriers don't call foreign numbers.
On the right, you will find an input field to insert your discount code.
Click apply, and you will see the discount applied to your purchase.
You can't apply more than 1 discount code at once. Also make sure that the code you have applies to the product you want to buy, and is valid.