After adding your purchases to your shopping cart simply click the cart icon in the top left corner of the page and then click the "view cart" or "checkout" button.
Now you are in the shopping cart/ checkout process. Enter your coupon code in the Coupon box and click apply
If your coupon code is valid you will now see the reduced amount showing in your shopping cart. This is normally a % reduction from your purchase but could occasionally be a fixed amount off for a purchase over XX amount. For example £50 off any purchase over £300. It all depends on what special deal is on for that particular coupon code.
As a final step you will need to either 1/ login using the option tab on the left of the cart, or enter your details to register an account on the 3dscanstore, from there just click the checkout button. Select your preferred payment method and checkout as usual, for the coupon discounted total!