Spent a day trying to sort this with out success until i found this You tube video
Basically the script it uses does everything for you.
wget https://git.io/vpn -O openvpn-install.sh && bash openvpn-install.sh
Seems legit to me
Took 5 minutes
Also i found a similar thing, maybe same script, on this web page.
The other thing it helps with is adding users. I could not find a “how-to” anywhere for adding more users after install. From the posts i found a lot of people have the same issues.