Running an private Overload server requires a few things:
1) Open UDP ports 7000 to 8001. Note: this guide does not cover opening these ports.
2) An installation of Overload.
3) olmod v0.2.7 or later.
4) Configure your server by modifying olmodsettings.json.
"serverName": "roncli's Testing Server",
"notes": "Contact email@example.com for details!"
You must set isServer to true and ensure the trackerBaseUrl is http://tracker.otl.gg to get listed. You should also set the serverName to name your server, and add any notes that you would like listed alongside your server within the Overload Game Browser. If you wish for your server to remain listed even after it is offline, set keepListed to true.