HDR not really for indoor photos. More for landscape where there is a large tonal range. If looking for tips on flash photography check out strobist.com, and go to lighting 101.
HDR will not make bad pictures good...it will bring details and lighting differences to a well setup picture. Personally, having used the HDR feature for quite some time now over the last few iPhones, it makes a WORLD of difference when you properly use it.