Event listing sort choice

Hi all,

I’m sure it’s basic, but I can’t find where to set the event listing setting to default the sort to the event start date when filtering by Upcoming. Right now my sort order has defaulted to ‘Add Date’ rather then event date. Looking at the field choices in ‘Event Custom Fields’ there isn’t a field to select for event date. Looking at the demo at http://wpgeo.directory/events/?etype=upcoming, that seems to be sorted by event start date. Can you guide please,

Thanks