Follow these steps to redeem your Kinguin Gift Card:
- Sign in to Kinguin and go to Redeem a Card page
- Enter the Kinguin Gift Card copied from the "Withdrawals" section in your Idle-Empire User Panel and click Redeem
- The value of the card will be converted into Euro balance
- Buy games on Kinguin and pay with your Euro balance
Note: You can find the official instructions here.