How can I add a promo code?

On the home page of your customer area, you will see on the right side of the screen the box "Promo Code"

Click on the product for which you have received a promo code
The box below appears:

Fill in the promo code you received and click on "Apply"

Enter your order by following the different steps on the platform. Click on "Validate my order" to reach the next page which gives you a summary of the ordered products.  
On this screen, click on the box "Promo code"

A new window appears, this is where you can enter your promo code

Fill in the promo code you received and click on "Apply"