I would like to introduce to you, the simplest and easiest way to install OpenVPN Server on Linux HDH that I know is openvpn-install. I have been using this script for quite some time now. It really saves me a lot of time and effort in setting up an OpenVPN Server.
Install openVPN
wget https://git.io/vpn -O openvpn-install.sh && bash openvpn-install.sh

- IP address: Server’s public IP address
- Protocol: The protocol you want OpenVPN to Use. Default is UDP Protocol
- Port: The port on which the OpenVPN Server will listen. Default is 1194
- DNS: Domain name resolution server. Default is 1, but here I choose DNS as 2 (Cloudflare DNS)
- Client name: VPN Client (Can be understood as the username of VPN)
After successful installation, the configuration file of openvpn will be saved at /root/.ovpn

Uninstall OpenVPN Server
bash openvpn-install.sh

Copy ovpn to local
scp username@remote:/file/to/send /where/to/put