sudo apt update sudo apt install openvpn -y
openvpn --config client.ovpn the .ovpn file need to be download/provided by the openvpn server. In my case is a openvpn server I have installed on a remote office pfsense router.
Manual Outbound NAT
https://forum.netgate.com/topic/68481/tutorial-configuring-pfsense-as-vpn-client-to-private-internet-access/4