Low light photography without flash requires high speed settings and a steady tripod. Any motion will blur the images, so if the activity on stage is beyond slow, your photos will still come out blurry. Cameras need light to focus, and without it you must know how to use manual settings.

But what you are asking help with is illegal. Why not just enjoy the show and leave your camera at home? What you are describing wanting to do may get you ejected from your concert, and maybe even the venue in the future. There is a good reason photos and cameras are not allowed in concerts, theatres and other artistic venues. Don't do it. It ruins the experience for others who are mindful of the law and common courtesy.