Glad that you’ve manged to make it work.
However the plugin Google Sheets Service Type has different workflow. It is not designed to be used with your Drive, but instead it works with virtual drive through google service.
The regular account is just a normal Google account that your application uses. Since regular accounts require the manual authorization step (going to the browser, logging in to Google and authorizing your app), you need to do this manually the first time and then save the token. There’s some examples in this page. After you save the token, your app can authorize itself without your intervention.
The service account is an account that is not associated with an user and that do not require manual authorization. You can create a service account in the Developers Console as described here. With this type of account, you use a private key file to authorize your app.
If you want to connect the user their personal account when signing in and working with personal sheets, you’ll need to use a different plugin instead:
Please check the demo setup and documentation for it, so it will help you better.
Thanks for understanding.