Nikon d3100 camera, shooting a concert?

I'm going to be taking pictures at a concert tomorrow.
i'm not all that familiar with my camera yet, and last time i took pictures at a concert, they weren't of good quality and very blurry.
The concerts are fast paced, "Screamo" genre if that helps you understand the setting (dark)

i know i need to change the aperture, iso, and shutter speed, but i don't know how.

When i get into the ISO sensitivity settings, i can only change the ISO sensitivity. I can't change the Auto ISO sensitivity, max. Sensitivity, or Min shutter speed.
It says "this option is not available with the current settings"

If you could give me a step by step guide on how to fix this, that would be a great help!

Added (1). I can't use manual, that's what messed up my pictures last time. So i need to figure out why i can't change my ISO settings, like when the error screen pops up and says its not available.

remember, i'm not used to my camera and have had nearly no experience with cameras. So try to make terms simpler >.<

Just switch the dial button to M for manual mode

I don't use Nikon, but the basics of photography is the same no matter the camera you are using. I use manual (once you can drive a stick shift car, you can drive any car).

I assume (dangerous, I know) that you will be using a media pass if you can use a DSLR, and will be at the stage front. I put a 50mm f/1.4 on my main camera and a 85mm f/1.8 on the backup camera. I preset the ISO for 1000, a wide aperture, then meter the shutter speed and make necessary adjustments.

EDIT: You will need to read your manual. Not all options are available in the different modes, the manual will tell you what is available for each mode.

If you don't have the manual, you can get it from the Nikon site.