When another user has shared a calendar with you, their calendar  name will appear in the Calendar section of the Scheduler section.

Calendar Overlay View
Shared calendars can be overlayed onto your own by clicking the check box to the left of the calendar name in the Calendar section of the Scheduler. The shared calendar appointments will display on your calendar in addition to your appointments and will be distinguishable by the color associated to the calendars. The calendar color can be changed in the Calendar section of the Scheduler by clicking the color box to the right of the calendar name.

Single Calendar View

Note: If you have Full-Access to a Shared calendar, then you can create a new event in the same way that you create events for your own calendar.