Auto-Fit game to fit all sizes of screen resolutions

Hello uAdventure team,
I created my first game using uAdventure 👍 when played on different computer screens, black borders appear on the left and right of the screen. how to make the game auto fit on all various screen resolutions? The top and bottom auto fit on all screens but the left and right don’t. So if the top and bottom auto fits then the left and right can too, how to do it?
Thanks,