Because they formed from only hydrogen and helium, we think that these first stars were very massive, very luminous, and very short-lived. In death, these stars gave the Universe its first supply of heavy elements. So everything heavier than helium was made in the furnace of these first few generations of stars. You, your computer, your jewelry, etc. are star stuff! Where does the iron in your blood come from?
1) The Big Bang
2) Supernovae of the first stars
3) It was always around