At the tab 'Teach' you can click the Calendar icon.
How to add an calendar event
Click + Event to make a new entry. Here you can select the subject, date and time for the calendar entry
Link your calendar
Click Link calendar to link the calendar with an external program. Paste the link that appears in the other calendar that you are using, provided that the other program supports this feature.
Export your calendar
Click Export calendar to export it as an ICS file. These can be opened in Microsoft Outlook or Google Calendar for example.