How to slow down shutter speed and aperture on my Nikon D3100? - 1

Can anybody tell me step by step please!
I just got the Nikon D3100 for christmas today, and I heard you can take a cool picture using a flash light and slow shutter speed.
Like this:
Sorry i don't know if you can see it or not.
:x But yeah! I'd love to know how to do that.

Shutter priority mode (S on the dial) then scroll the adjustment wheel.

1) Put your mode dial to 'M' or Manual Mode

2) Change the shutter speed from anywhere of 8 to 30 seconds.

3) Depending on the lighting, change the f-stop to correctly expose

It is called light graffiti

You need to put your camera on a tripod or other stationary location
You need to do this in the dark
With the camera in the bulb setting, press the shutter release and hold it open while someone waves a flashlight, penlight or other light emitting device around.

You will need to adjust the aperture of the lens to assure that the image is not over/underexposed. It is simple to do the tests.

If you manually focus the lens on the light in position, you will have sharp images. Usually it is too dark for any camera to auto-focus when shooting light graffiti