You can subscribe to any calendar that has at least Read permission.
To subscribe to a calendar, perform the following steps:
In two-pane layout, select Calendar from the service selector panel in Convergence UI . In three-pane layout, click the Hamburger menu (three line menu) icon in top corner of the Convergence UI, then, click Calendar.
Click the Create or Subscribe to Calendar icon on the Calendar toolbar on the left pane in two-pane layout.
Click Create or Subscribe to Calendar from the Actions drop-down list on the Calendar toolbar on the left pane in three-pane layout.
Select Subscribe to Calendar from the drop-down list.
The Subscribe tab appears on the right pane.
Enter the user name or the email address to search in the text box provided.
A list of all users matching the search criteria are listed in the search pane.
Select the calendar that you want to subscribe to by selecting the corresponding user name.
All calendars belonging to the user are listed in the right pane. For each calendar, the permissions assigned to the calendar are also provided. All calendars that are already subscribed by the user and those that cannot be subscribed by the user are disabled. These calendars cannot be selected.
Select the calendars to subscribe to by selecting the corresponding check box for each calendar.
Click Subscribe.
The selected calendar is added to the list of subscribed calendars in the Calendar service pane.