Prerequsites :
You should have a remote OpenVPN server running
You should have an openVPN client config
Install OpenVPN client packages
pkg update
pkg install openvpn
Now create openvpn folder in /usr/local/etc/ . I always create seperate folders for client and server . So I can use it if I need to run both server and client from a same device .
mkdir /usr/local/etc/openvpn/client/
Now you can copy a sample client config to this location , so the sample config will be in :
/usr/local/share/examples/openvpn/sample-config-files
cp -R client.conf /usr/local/etc/openvpn/client/
You can configure your client config with your server IP , type of inetrface etc . I presume you already have this config as this tutorial is not about a complete openvpn server-client set up . So now you need to update the /etc/rc.conf file , you need to enable your openvpn service and also point the client config here as below :
Once this is saved , you can start openvpn .
service openvpn start
So if everything fine you should see your new interface as below . If its not getting an IP nor creating that interface , you need to check the openvpn logs . This is something you specified in your client config
ps ax | grep openvpn
/usr/local/sbin/openvpn --cd /usr/local/etc/openvpn --daemon openvpn --config /usr/local/etc/openvpn/client/client.conf --writepid /var/run/openvpn.pid