How to do light graffiti?

I have a Nikon P100 digital camera, but i'm not sure how i would go about doing the light graffiti. I know where i need to do it and that it needs a tripod or hard surface but what settings would i use? And where do i find them on the camera?

Turn the mode dial to "S". Now select a long shutter speed setting. Make sure your environment is nearly totally dark or you will get overly bright photos.

Try to keep the shutter open as long as possible.go into a dark room and take a picture.(no flash)

You have to trick it into staying open using the shutter priority mode.

Remember to place your camera on a tripod