To return to your calendar, use your browser's Back button.

Using the toolbar
The top part of the Organizer Web Calendar workspace is the toolbar. If you're viewing your calendar in Day, Week, Month, or Year view, there are drop-down boxes and icons that help you change views and perform tasks like creating a new entry or going quickly to today's date.

See also:

Organizer Web Calendar differences
The Organizer Web Calendar workspace
Calendar views
Changing views
Moving between sections
Moving from year to year in Calendar
Moving to a specific date