The hanging hole can be placed along the top of the calendar or the bottom of the calendar.
The placement depends on the the artwork set-up and print spec.
You can configure this option once you have uploaded your artwork.
Recommended hanging hole placement:
Portrait, 1 page per month, single sided: top of calendar
Landscape, 1 page per month, single sided: top of calendar
Portrait, 2 pages per month, double sided: bottom of calendar
Landscape, 2 pages per month, double sided: bottom of calendar
Screenshot example:
Taken from Document Preview page
Spec - A4 portrait, 1 page per month, single sided, hole at top of calendar