how we can create client ID & Client Secret in Google sheet:Create spreadsheet.
For the Create spreadsheet step, Google developer console account should be created and subscribed - https://console.developers.google.com/.
APIs for Google Drive and Google Spreadsheet should be enabled.
Client ID and Client Secret should be generated from the Credentials tab.
For further details, please refer to the Plugin Reference Guide3 - Appendix 25: Google Sheets Refresh Token Generation