In this post I will describe how to configure Thunderbird Lightning addon to synchronize with your google calendar. This post will be more for a bidirectional configuration, in which you will have read and write access to your calendar from Lightning.
Downloading Provider for Google Calendar
If you need both read and write access to your calendar, you need to install the Provider for Google Calendar from addons.mozilla.org.
1-Open the Provider for Google Calendar addon website.
2-Download the file by right-clicking on the Download now link and choosing Save as.
Installing and configuring the add-on
1-To install the add-on, select the Tools menu from the Thunderbird menu bar and click the Add-ons menu item.2
2-In the Add-ons window, click the Install… button and select to the downloaded file. Click the Open button to install the extension.
Getting an XML link to your calendar
To access your calendar data, you need to retrieve your private XML URL from the Google Calendar UI. Follow these steps:
Open your Google Calendar by going to the Google calendar website.
Select Settings from the top and choose Calendar settings.
Select the Calendars link at the top of the settings page. A list of Google calendars is displayed.
Click on the Calendar you would like to use in Lightning.
On the Calendar details page of your calendar, scroll down until you see Calendar address and Private address.
Right-click the XML button of one of the two options and select Copy link location.
Note: You can’t use the same link when creating a new calendar in another computer, as the provider resets the url. You need to copy the new url and do the same process again as the url changes.
Importing the calendar into Lightning
To import the calendar into Lightning, please follow these steps:
1- Go to the File menu at the top of the Thunderbird window and select New. From the sub menu select Calendar.
2- Once the wizard opened, select On the network from the available options and click Next.
4- In this pane, you can select a name and a colour for the Google Calendar. Click Next to continue.
Now, a popup appears in which you have to enter your GMail username (with or without the @gmail.com part) and password and choose wether you want Lightning to save your password. Once you click Next, Lightning creates the calendar and provides you with two-way access to the google-calendar.
And you’re done!
Some portions of this site have been quoted from “https://support.mozilla.org/en-US/kb/using-lightning-google-calendar”