I haven't been taking pics for a long time but the flash is a very complicated thing to get right. There is no way I can explain it you need to hit some web sites.
I have seen some pics on bright sunny days....portraits, that a "fill flash" made a huge difference.
In this pic the flash was bounced off the ceiling to create a "fill" to the existing main light, the lamp.
In this pic just the flash aimed directly at the people. The pic has lost it's atmosphere and is rather hard and flat.