you need to start the game, go into the options (that gear-icon on the top-right) and there go into the video-settings. In that screen you can set the resolution on the right side of the screen. If the game fails to start due to wrong video-settings, try to delete the File "graphics_options.xml". It should be located in your Documents-Folder: "...\Documents\My Games\SimBin\RaceRoom Racing Experience\UserData" After a restart it should choose resolution automatically and after that you can change it in the menu as described above.