How to connect a local network to an OpenVPN server?

**NethServer Version: 7.1
**Module:VPN
Hello.
I have a gateway, a local network is connected to it.
3 providers work.

There is a VPN server to which you need to connect the gateway.

Problem 1 - the ovpn configuration file is not accepted.
Problem 2 - I do not understand how to direct LAN traffic to vpn
Problem 3 - I generally do not see the connection settings of the gateway itself to the vpn server, this is a very necessary setting, it is much more important than creating your own vpn server

I specify the question.

How to connect a local network to an OpenVPN server?