The calendar is a full-featured Open Webmail tool that allows you add daily events and reminders to an organized schedule. To view the calendar, click the calendar button
( ). You will then be redirected to the calendar page:

The current day is highlighted in a lighter grey than the rest of the days in the month.

To view a specific day, you can click its corresponding number. This will take you to the times and events for that day. You'll notice that there is also a specific toolbar for the calendar. see The Calendar Toolbar for more information.