Please note that this is also the initial step to allow international delivery in our official plug-ins ( Magento, Prestashop & Woocommerce)

You can find the setting in Admin > Delivery Settings. Click the € icon in front of the international delivery method you wish to configure.

Next, click on the "Add price zone" button. 

In the new screen, you are able to select the available countries for the zone. For each weight class a price needs to be entered. It is possible to create multiple price zones. 

Afterwards, don't forget to save your configuration as well or your changes won't be applied.