Add the Klarna Checkout Page to your site
You add the Klarna Checkout page in back office and this is how you fill in all fields necessary.
Step 1
Go to the Web Publishing module in back office, select your site and add a regular page to state the "terms and conditions" of the merchant. This page link is needed to be sent to Klarna.
Step 2
Add a new page of type Klarna Checkout, edit the page and set the mandatory content and settings fields.

Under the Settings tab, link to the terms and conditions page and set the merchant ID.

Enable Klarna checkout in wwwroot\bin\Litium.Studio.AddOns.Klarna.dll.config file.

Set the CheckoutTestModeCallbackUrl parameter as shown in above image if your computer is behind a firewall.
The setup is now complete.