Assembly is as seen in the photo.

Launcher requires some letting in. 

For more power, use more rubber bands (may lead to more stress on catapult so have caution

Catapult must be superglued in place (Except for launcher) so that parts do not fall apart during launching. 

Should be printed in petg or some strong but flexible material. 

Ammo can be anything that fits into the launch cabin. 

Parental supervision and assistance should be provided to kids under 13

Enjoy!

Optional: There are extra slots on the pieces the launcher is in between. They can be used to change the angle for which the ball launches from. I recommend using a thin metal rod for the slots. 

I am not liable for injuries caused by device