In my novel, the MC gains employment as a security guard. She's given a uniform which includes a pistol (automatic, not a revolver). She isn't given any formal training or instruction for it and feels uneasy about using it, fearing an accident or mistake. Luckily, she has a friend who was in the army and asks for advice about how to handle the firearm. My question is this: What advice would she be given? (I'm particularly interested in the opinions of anyone with military experience).