The native ownCloud documentation is complete and extensive, but therefore maybe a little too mighty for a quick start. There are lots of tutorials available on the web, that sum up the most important steps, you may find one that suits you (I used this one which is but in German language).
I had troubles setting up the database with mySQL (can’t remember the details), so I decided to use MariaDB instead. This works flawless since.
Let’s Encrypt certificate
A server containing personal data should always be secured in the most proper way possible, thus providing encrypted access. letsencrypt.org has lined up to make encrypted connections to servers ubiquitous. Lucky for me, letsencrypt.org had gone public beta a month before I built my server.
Installing the client and setting up the certificate with auto-renewal is explained very easy and comprehensible in this tutorial. Thanks to Erika for that.
I needed to change the email address I had provided during the setup process later (updates on your renewal status are sent to this account). The letsencrypt client does not yet support a change of the address, but it uses certbot, which has some command-line options for that.
Part 4 will deal with the issue of backup.