(1) Open your Klaviyo account and navigate to settings > Account > API keys > Create Private API Key
NOTE: PLEASE ENSURE YOU CREATE A FULL-ACCESS API KEY
(2) Copy this API Key and fill it in the app’s Email service provider section. Navigate to settings > Integrations > Email Service Provider. Select Integration as Klaviyo and fill up your Klaviyo Private API Key and save it. 
(3) As soon as the customer places an order, their contact details will be fetched in your Klaviyo Analytics Data. Along with their purchase details, you can find them in Klaviyo Analytics > Metrics > HulkProductoption section
NOTE: Only one email service provider can be Integrated at a time
