Users with an Administrator profile can view all meetings on the calendar for any user. Users without an Administrator profile can still view other users' calendars, as long as they have the appropriate permissions (see Data Sharing Settings for more info).
To view another user's calendar:
In the calendar, click the My Meetings & Calls dropdown.
Select the user(s) whose calendars you wish to view.
You can also create a Group to quickly access and view calendars for a specific set of users.
To learn how to create a Group, refer to the Create Groups article.