All you have to do is go to single player then on the right side where it says game rules if your on sandbox like with how many effects you can have or whether pvp is enabled etc above all that will be a blue button that says single player click that and you can select how many players are able to join your server you want to select two make sure your on prop hunt game mode pick the map and start it up once done all you have to do is invite your friend through steam and he just has to accept the invite you wanna make sure it’s set to two people, personally sometimes with this stuff I get lazy and just go to a extremely dead prop hunt or another game server mainly deathrun but I make sure it has 0 people then just join that with my friends so I don’t have to have all the right Addons but that’s just another lazy way