The setup of this integration is handled entirely by the Loyale backoffice.

You will need to have a Klaviyo API Key to authenticate the integration.

Your Klaviyo API Key can be found in your Organization > Settings > API keys section.

Scroll down to 'Private API keys' and choose 'Create Private API Key'

For more details click here

The setup has one property called Merge Customers. In the case where the Klaviyo account already has profiles, this setting will let Loyale overwrite any profiles that have the same email address as the Loyale customers, with the data from Loyale.