On the 12 tribes and Kohanim and levyim (pronounced levi'im), as far as my memory goes that is:
There were three fore fathers to the Israelite nation -
Abraham -> Yitzhak (who was to be sacrificed by his father to god as a test of faith) -> Ya'akov (Jacob), whose name means "he who grabs the ankle" - for it was told that he had fought an angle in his dream and won the fight by grabbing at its ankle. So Ya'akov was also called Israel had twelve sons who where the fathers of the twelve tribes
Ya'akov's sons:
Reuben - first born, name means look, son,
Shim'on (Simon) - name means listening,
*** Levi *** - He his the fore father of the priests tribe whose most prominent members were Moses and A'haron. The Kohanim were decndents of A'haron who was the first "Kohen gadol" or high priest. The levites are lesser priests then the Kohanim.
Yehuda (Judah) - his decedents have kept their identity through the millennia - they are today's jews.
The rest are Dan, Naftali, Gad, Asher, Issachar and Zvulun.
Last were Joseph (described as a prophet in the bible) and Benjamin.
Wow, that came out long, now don't got me started on the angles
