You can configure past events in three ways:
1) Display past events
This will show all of your events in ascending order. From oldest to newest.
2) Hide past events
Once an event has finished, it will no longer show to your customers
3) Display todays date first
This will still let your customers access past events, but will load the calendar on today's date.
You can configure these settings in the 'settings' tab in the editor: