Unable to add my google account to Provider for Google Calendar (add-on)

I have recently found [https://support.mozilla.org/en-US/kb/using-lightning-google-calendar this article] about how being able to use Google Calendar on Thunderbird, so I have downloaded and installed the add-on from [https://addons.thunderbird.net/en-US/thunderbird/addon/provider-for-google-calendar/ here]. I have been following the steps and I don't see any option to add my Google account, according to [https://support.mozilla.org/en-US/kb/using-lightning-google-calendar the article], I should be able to add it by going to File > New > Calendar > On the Network, but I only see iCalendar(ICS) and CalDAV there. There's no Google Calendar option. What should I do? I'm using Thunderbird 78.2.1 (64 bit) on Kubuntu 20.04 (Linux).