Plutonium

Hosting a server is not hard but you still need to understand/learn a few things/get used to how it works.
If you plan on hosting on Linux it's a lot harder for beginners yes. It's not even officially supported by Plutonium so you'll have to use tweaks and specific versions of software etc.

Based on the name and version number, I’m guessing you’re using this mod: https://forum.plutonium.pw/post/63067
You need to download Cold.War.Overhaul.Mod.zip, not the source code.

Either change it in you config or change it like any dvar via the console and apply it with vid_restart