Ok so here is what I do. I use S to try and shoot (I hit a lotta buttons but I thought I saw s somewhere so was my go to attempt). I also tried arrow directions and attacking with the broom. Idk if those are the right methods or I dumbed xD I'm hoping I just dumbed :p
Oh I think I understand. BroomStickBot is metroidvania and you can't shoot when game starts. It goes without saying that you have to explore and find powerup to allow shooting.