Left and right arrows to move or A and D, space to shoot, if you shoot on the ring walls it won't damage the monster so use the ring holes to shoot, and watch out for the health bar.
Thanks to my scratch instructor(who is @daniel-udemy-3(on scratch)) I could complete this project and don't forget to check out my other project Shoot the Monster Easier here is the link it is also in the comments https://scratch.mit.edu/projects/409622594/