You have pretty basic controls in this game. You can use W S A D keys to move or just AROW KEYS to move and jump through the game's fifteen levels. You don't need a Mouse, just working keyboard.
If you can't reach stars or if you think u can't jump that far, use objects on the map and move them with your body in order to reach them.
Sometimes going straight into the ground level you can find hidden stars and treasures so dont hesitate
EVERY Object you see you can use it or either jump on it
If you press and hold W or Arrow UP you will jump longer