To sync a custom list of events from Timeline:
1. Go to Timeline.
2. Click on the plus sign (+) of all events you'd like to sync with your calendar.
3. You'll see a pop-up letting you know that your events have been added to the list.
4. Click on the list icon.
5. Hit the blue "Add-to-Calendar" button.
6. Select your preferred calendar.
Here's a demo video on how to sync a custom list of events from Timeline: