How does openVPN work at a high level?

Question

VPN

I just need to understand how openVPN works at a high level. No nuances, no details.
1) That is, it's just software that is installed on one computer and acts as a server. All. And clients simply connect to it. That is, openVPN is like a web server, and clients are like browsers, right analogy? The server itself (openVPN) does not initiate the connection, it only processes requests from clients, right?
2) openVPN (server) is only installed on one side (computer). On the other side (client) openVPN is not installed, right? To make a request to openVPN (server), you need to send a request using the openVPN client, which can be written in anything - python, c#, c++. It doesn't matter to the server itself, right?
3) Why here https://openvpn.net/index.php/open-source/document... says "can be used when OpenVPN is running as a client or server."
First, it's an interface for managing the server, right?
second, that how can OpenVPN be run as a client? OpenVPN is a server by definition.
4) What is the client.ovpn file for? Why does it look like it's for a server? That is, it has various settings that only make sense for the server.
5) stackoverflow.com/questions/1091861/how-do-i-progr...
Why does the PS seem to mix client and server together? That is, he wants to create a client in C #, why does he run the openvpn.exe file - is this a server ? Or am I not understanding something?

Answer 1

openvpn.exe is written in such a way that it can be both a server and a client. The mode of operation is determined by the configuration file.
Formally, yes, it was necessary to write openvpn-server.exe and openvpn-client.exe. And put on a computer or one binary, or another. But in any case, there are a lot of identical functions inside, which are both in the client and in the server. For simplicity, we wrote everything in one binary.

Answer 2

Thank God everything you wrote is wrong, at least vpn and web server are protocols of different axis levels, so analogies are not appropriate