[Owncloud] Import existing contacts to Contacts app?

[Advrk Aplmrkt]

Hello,

This is kind of basic, so I apologise if I am missing something obvious.

Is there a way to mass import an existing set of contacts into my
ownCloud instance? I have a bunch of contacts that I hope to migrate
to ownCloud, but can't manually re-enter each one because there are so
many!

If so, what is the preferred file format?

Thanks!