1. Enable Files Connect – https://www.infallibletechie.com/2016/08/how-to-enable-salesforce-files-connect.html

2. Create a Permission Set with User License None.

3. Go to System Permissions and select “Files Connect Cloud”.

4. Assign the Permission Set to the user.

5. Go to Security Controls –> Remote Site Settings.

7. Add the below remote site settings.

8. Create Authentication Provider – https://www.infallibletechie.com/2016/08/how-to-create-authentication-provider.html

9. Define External Data Source – https://www.infallibletechie.com/2016/08/how-to-define-external-data-source-for.html

10. Go to Files tab to check.