how to build private app to poll google sheet new row

Hello,

I am building a private app aiming to:

1. poll a google sheet’s row adding;
2. get specified column data on the new row;
3. upon the above trigger, obtain OAuth 2.0 authentication to an Adobe cloud-service;
4. post API request to that Adobe service with some data copied from the google sheet’s new row.

I am building private integration app becaues Zapier Webhook does not support OAuth 2.0 authentication. I can setup the OAuth 2.0 part in my private app. Would anyone advise me how to setup the google sheet polling part?

Many Thanks.