You have to scroll down, then it says the following under "10% voucher":
10% voucher
minus 10% instant discount "CANONXMAS

From 02.12.19. to 08.12.19. there is a 10% discount on the Canon photo and video range with voucher code "CANONXMAS".

To benefit from the promotion, simply enter the voucher code during payment and the discount will be deducted directly.

Only for the specified promotion period, maximum three products per customer per order. Imported products are excluded from the promotion.

So you just have to enter the code at checkout and you'll get 10% off :-)