Complex sentence: Then he went to the oilfields of Texas and Oklahoma and then found work as a tool boy, a messenger and sporting editor of a newspaper before going to Los Angeles to star in films, but no producer wanted him.
Split into simpler sentences: Then he went to the oilfields of Texas and Oklahoma and found work as a tool boy. He was thereafter a messenger and sporting editor of a newspaper before going to Los Angeles to star in films, but no producer wanted him.