To see how the carnival ride works, test it out. When playing, you'll ride on a cart and blast away approaching enemies. Just make sure no enemies touch the ride - too many hits from an enemy and the cart will explode!
Click Play to test.
In the experience, walk up to the character under the Play It sign and press E to open up a menu. On that screen, click Join Game.
When the ride starts, left click to shoot the blaster at enemies. Watch the cart's health at the top of the screen and try and make it to the treasure room at the end.
Either finish a round, or press 1 to use the mouse. To stop testing, press the Stop button or press Shift+F5 on the keyboard.