Help taking photos with Nikon D3100?

I'm wondering how to take a photo that looks like this

I understand that this type of photo is created by using a long exposure time, but I need help changing the settings on my D3100

Change the settins is indeed explained in the manual.

The example you posted is a bit tricky, this seems to me a 10 seconds exposure in daylight. For that you need a tripod and a neutral density filter.

Check this little tutorial out. Nikon has a how to on this subject. I've used this article's information when taking waterfall/water pictures with my Nikon D3000.

http://www.nikonusa.com/...aters.html

Key elements…

Pick the proper time of day
Maybe use and, neutral density filter to allow slow shutter speed
Manual camera settings for extended shutter opening speeds
Sturdy tripod
Remote shutter release, Nikon has one
Maybe Photoshop a new sky into the image