The stackorigin will guide you how can you Open another person’s Calendar in Outlook.

• Open your outlook.
• Click the calendar icon in the lower left of Outlook.

• In the Manage Calendars group, click Open Calendar, and then click Open Shared Calendar.

• Type a name in the Name box, or click Name to select a name from the Address Book.
• Click “OK.” 
• The name of the shared calendar will also appear on the left-hand side of the screen with checkbox’s. Uncheck this box to close the shared calendar. You can recheck this box later to view the shared calendar again.