Add items to shopping cart.
Click on Cart icon and then click Go To Cart button.
Check your order and click Proceed To Checkout.
Enter your Epic Games e-mail address.
Please enter the same email address that you use to sign-in to your Epic Games Account here: https://accounts.epicgames.com
Enter your Fortnite display name.
You can find it at the top right corner after you login to https://accounts.epicgames.com: