Looking at the manual:
https://doc.owncloud.org/server/10.0/user_manual/pim/
But.... Neither calendar nor contacts appear in the apps list.
Wait, it's in the market! I got it! How does it work?
Aha, there's Docco!
"Wolfgang Fahl edited this page 10 hours ago"
"https://doc.owncloud.org/server/9.0/user_manual/pim/contacts.html points here in an endless loop"
Oh dear.
Oh dear.