Configure this app to access a Google Sheet
Go to Credentials tab, click on + CREATE CREDENTIALS and choose Service Account. Set the name and description (the email will be generated for you), and click Create.
Back at the console, click on your Service Account, and click ADD KEY to create a new key. Choose JSON and click Create. Save the file to your computer (and rename it if you need for better reference in the future).
Copy the Service Account key from the file downloaded in the previous step, paste it into the text box, and hit Enter to save it in the config database collection.
Copy the client_email from the file in the previous step. Open your Google Sheet, and share the Google Sheet with the client_email so it has access to read your data.
Copy the URL of your Google Sheet from the browser's address bar and paste into the text box. Hit Enter to save the Sheet Id in the config database collection.
After completing the configuration process, go to the Sheets page of this app and see if you can see the data being read.
Click Reset if you wish to reset the configuration and start the process over again. This will clear the configuration data currently saved in the database.