When Should I change/use ISO, D-lighting, Active D-Lighting, WB, etc.?

hey yall! I recently got a nikon d5000 about a week or so ago and I never really understood when to use these features. Light is a very important part of taking a picture and I just don't get when to use ISO, d-lighting, active d-lighting, white balance and all the other features that adds more or changes... show more hey yall!

I recently got a nikon d5000 about a week or so ago and I never really understood when to use these features. Light is a very important part of taking a picture and I just don't get when to use ISO, d-lighting, active d-lighting, white balance and all the other features that adds more or changes light! ughh, could someone please go into detail when I should use these? I really want to know!

Thanks (:
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