Before You Begin
By default, Microsoft Outlook opens to the Inbox. Look on the left side at the bottom of the Navigation Pane for the Contacts Folder.

1. Try It: Log into Office 365
Go to the Office 365 portal:
https://portal.microsoftonline.com.
Please log in.
Go to Outlook.
You should see the Inbox.

Now, Try This: Find the Calendar
Go to the Navigation Pane.
Select the Calendar.

So far, so good...

Outlook->Inbox->Calendar