From when and how can I convert bonus points into a voucher?

To view and redeem your bonus points, you must be logged in.
In your account, you will find the ‘Rewards’ button in the menu.
 

From 1,250 bonus points, you can redeem your first reward.
You do this in the same screen where you can also view your points balance.
 

Once you have redeemed a discount voucher, it is automatically linked to your account.
During checkout, you only need to activate the voucher.
To do this, click the ‘Proceed to checkout’ button at the top right; the discount will be applied immediately and is visible when it applies to the selected products.
 

For more explanation and a complete overview of all rewards, click here.