To get started, you might want to use a stable rest or a sandbag to help cut down on any movement from you while shooting. I know it’s just a defensive pistol, but when you're zeroing it in, you really want to keep things consistent. Take your time with it, fire off some slow, focused groups of about 3-5rds. Instead of just adjusting based on a single shot, look at where the center of those groups lands and make your adjustments from there. Keep doing this until your aim lines up perfectly with where your shots are hitting.