You rotate it, then shoot (but you only have one shot). Shoot with the spacebar. The rotating controls are rhetorical.
This is an original project I made! Remix it to put the script into whatever use you feel like it. Once you shoot the ball, it will ricochet just like in any other game you've played with similar coding. Like World of Tanks ;) Also note, the ball does glitch due to the inability of speed Scratch can keep up at, and sensors will hit each other. Just note it will glitch at times when one sensor detects first.