Integrating with Google Calendar - Export & Import
Configure Import of Events
ActivityTimeline also supports the import of events from Google Calendar (Only Cloud). Users can integrate their Google Calendar with ActivityTimeline to have their meeting and OOO automatically populated.
To setup integration please follow the steps:
Navigate to My Account in ActivityTimeline → Calendar Integration tab.
Click 'Import from Google Calendar':

Approve integration by clicking 'Continue'
Choose what calendars to import and click ‘Update’:

Once connected, your Google Calendar events will automatically appear on your ActivityTimeline schedule.

How Imported Events Work
You can decide how imported events should be treated within ActivityTimeline. There are three main options depending on your workflow:
1. Use for Planning and Automatic Time Tracking (Default)
By default, imported events are:
Displayed on users’ timelines. On the Planner, all imported calendar events are grouped into a single “Calendar Events” line.
When you click on it, you’ll see a detailed list of events for the selected day or week. In the Workspace, the full list of calendar events is displayed by default.
Counted towards workload and capacity (OOO events reduce available capacity).
Automatically counted as time spent once the event has passed.
These events appear in Planning reports as workload and Timesheet Reports as time spent by the user.

2. Use for Planning and Manual Time Tracking
If you prefer not to automatically count calendar events as time spent:
Go to Configuration → Timesheet Settings → External Calendar Worklog Behavior.
Select Treat none as Worklogs.
With this setting:
Past calendar events will not count as logged time automatically.
Users can manually log time against Jira issues from these events:
Click the event → Log to Jira → complete the Log Work dialog.
The event will then appear in grey to indicate that time has been logged.

3. Use Only for Time Tracking (Exclude from Workload)
You can also import calendar events solely for time tracking purposes, without having them affect team capacity.
This is useful if meeting time is already included in Jira issue estimates and you want to avoid double counting.
To enable this:
Go to Configuration → Advanced Settings → Custom Functionality.
Add the following line: IGNORE_CALENDAR_EVENT_ESTIMATE
Click Update.
Important Notes
The integration initially imports 500 events, and subsequent synchronizations will automatically fetch all remaining scheduled events.
The synchronization frequency for shared calendars between Outlook, Google, and ActivityTimeline is approximately every few hours.
ActivityTimeline always uses the event time from the source calendar (Google Calendar).
If you do not plan to attend a meeting, set your attendance to “No” in Google Calendar. Pending or tentative events will still appear on your timeline.
Events cannot be edited directly in ActivityTimeline. To change or remove an event, update it in Google Calendar.
To trigger synchronziation, users can also click on the sync icon on Calendar Integration page:

For a more comprehensive overview, please, refer to the video guide below:
https://www.youtube.com/watch?v=bcLUJBS5bkQ&t=1s
Configure Export of Events
Users can export their schedule from ActivityTimeline to Google Calendar.
To build one's timeline into Google Calendar, follow the steps:
Navigate to My Account in ActivityTimeline → Calendar Integration tab.
Click on the Renew Calendar Link to generate a unique iCal Datafeed URL.

Open your Google Calendar: https://www.google.com/calendar/
Find a field Other calendars and press on the plus sign (+), select from URL in the pop-up menu
You will be redirected to Settings where you can add a previously copied link.
Google does not provide any control over the Calendar refresh rate. Google automatically gets calendar updates approximately every 8 hours.