Rant regarding store bought pistol sighting

I bought a glock 19 5th gen and don't know how to sight it properly. I've noticed my pistol has 2 sights on it, one is wider and the other is smaller. Is this called the delta point what not? In my mind I thought a red dot sight would help my sighting but I was told its not necessarily true to the delta sights. Can someone explain to me how sighting delta sights work what their advantages are and how do I properly sight them?