Hi all,
Is there any tutorial about user auth & how to connect plasmic to database like Firebase / airtable?
You should be able to connect your plasmic component with any data source as usually done in react component.
You can simply add the Firebase/Airtable logic in the Wrapper component provided when you sync your Plasmic Component
https://react-firebase-js.com/docs/react-firestore-database/getting-started#components
This link has details about react firebase integration. You can replace the react component in examples with your Plasmic design components.