Sharing/synchronizing calendars

I bought a MacBook Pro for my wife yesterday and want to share calendars on my MacMini so that we avoid ":double-booking", which seems to happen all too frequently. Both machines are running OS 10.9.3, are signed into the same Apple ID and are — think — connected iCloud. The address books seem to have been shared. Internet connection is fine. But I cannot get the calendar up on the new computer. I have no problem with iPhone and iPad. So, obviously, I am doing something, and probably something very basic, incorrectly. But what???