I can't figure out how to take night shots with my new Fuji s8200
Taking pictures at night is just like taking pictures during the day, except it's darker. In order to get enough light to the image sensor, you need to either increase the sensor sensitivity (increase the ISO), open up the aperture (smaller f/numbers), use a longer exposure (which may require putting the camera on a tripod or other stable platform), or a combination of the three. Or put more light on the subject, perhaps by using the flash.
The flash on your camera doesn't put out very much light (when compared to the sun). You can't use it for subjects far from the camera, or when you want things at different distances illuminated evenly.
You didn't state the model of your camera so I'm afraid I can't tell you how to change any of the three settings I mentioned in the first paragraph.