This video teach us that how can we see multiple calenders at the same time. For example: calendar(by default) and cloud first team calendar. We can also view multiple calender's at the same time in the overlay mode. We can select multiple calender's under the tab my calenders. Earlier we were able to see single calendar at a time.But in Outlook 2013 and in newer versions of Outlook we can see multiple  calender at the same time.