Our "higher selves"?

I've been interested and been researching about spiritual / religious related things like astral planes, our "higher selves", our physical bodies, our astral bodies, astral projection, "silver cords," etc. I understand what our astral bodies do, and I understand that silver cords are I guess what connects our astral body to our physical body. But I was reading about our "higher selves" on wikipedia (a href="http://en.wikipedia.org/wiki/Higher_Self)" rel="nofollow"http://en.wikipedia.org/wiki/Higher_Self…/a and I know it means the "real" you, but it starts talking about groups of higher selves and I don't understand any of it. I don't understand what an energy stream is and it also talks about the third, fourth, and fifth densities - the third being the physical universe, the fourth being where dreams, astral projects, and out of body experiences occur, and the fifth being where the Higher Selves live. Where IS the fifth density? What are densities? It also says that, according to the group of higher selves, the simultaneously-incarnating higher selves