For an ideal night shot, you use a low ISO (like 100), a wide aperature, and most importantly, a slow shutter speed. A shutter speed of 15 seconds would be good, which means the lens is open for 15 seconds. Do not use the flash. It is also helpful to have a tripod for your camera.
To ensure a good photo in indoor/night setting, use a tripod whenever possible during shooting. Use the "M" (manual mode - present on the dial) and keep the ISO as minimum as possible (50-200 ISO is ideal). Use a shutter speed of anywhere from 2-10 seconds. Experiment around with these settings, since every situation requires a different shutter speed.