When a consumer selects the 'When' button or the calendar icon on the course confirmation email, it opens a dialog that displays the .ics file which is the iCal file. Many calendar programs use the iCal file to allow for an import of the dates of the class. The consumer would need to explore what options are available for the calendar program or app they are trying to use.
On the Admin side, staff does not have to do anything to make that iCal file option available on the confirmation emails. It is automatically included by default.