I am using the google adwords API to connect with adwords and list all the campaingns. I am connecting with OAuth to the Adwords account and become an access_token and an refresh_token, which I am saving into the DB.
Now I am trying to make this example: https://github.com/googleads/googleads-php-lib/blob/master/examples/AdWords/v201802/BasicOperations/GetCampaigns.php
But my access_token and my refresh_token are in the database and all the API OAuth2 credentials are in one configuration array.
How to query hte google adwords service with this credentials?