I forget what HDR stands for, but its a series a pics layered on each other. take one pic at the correct settings, and take 2-4 more, each one is +1 or -1 in exposure, so two that are over exposed, two that are under, in order to get all the highs and lows in the scene to get full detail. so u take -2 -1 0 +1 +2 exposure.
that was a crappy explanation. lol