MrParadiseDr Private game means private to friends that's what should be displayed.
To host a custom game you have to do some steps on your side which are easy if you have decent networking knowledge.
Otherwise the guide has an introduction that tries to explain everything you need to know.
Take your time to read it all from the top and come back if you still need help to get it working https://plutonium.pw/docs/custom-games/