Installed it from where? If from the Mozilla add-ons repository then you don't need to do anything else, because the "integrated" one is not any different from the one in the repository. More importantly, what issue are you having with Lightning?

Thanks for the reply. Yes, it was from the Mozilla repository, Lightning ver. 68.9.0. I have recently installed Thunderbird on Windows 10, and added Lightning and Provider for Google calendar. All seem to have installed correctly except the Lightning calendar only downloads events from the Google calendar but does not upload new events entered. It appears to be working in read only mode. I have uninstalled both of these add-ons and re-installed them both, but no improvement. Provider for Google calendar is ver. 68.2.1