Any tips on nightime shooting ie photos as a long exposure. Why are there so many options for exposure time?  Wh does each option mean. Thanks

Depends entirely on what youre shooting. The longer the exposure the more light is let into the lens giving you a brighter picture. However the longer the exposure the harder the picture is to take as the shutter is open for longer and will catch more movements. ISO can also come into play for night shots but if you could give some information on the what youre shooting I could recommend settings.