When you're in the game, press F9 to open the settings screen.
The configuration is saved when you save the game. You can find the saved XML configuration file in .. \ My Games \ FarmingSimulator22 \ modSettings \ advancedGameplaySettings.xml
Multiplayer support has not yet been tested with this release. Full support is planned, so unless you know what you're doing, my advice is to only use it solo for now.