The Klarna Checkout module for PrestaShop can to be downloaded from the PrestaShop marketplace.
Once installed and activated, the module's settings can be found by selecting Configure next to the Klarna Checkout module in your store's Module Manager.
Prerequisites
When using the Klarna Checkout for PrestaShop module, for a direct integration of Klarna Checkout, you will need a Klarna merchant account, for which you can sign up here.
An SSL certificate is required for the Klarna Checkout (KCO) module.