Complex sentence: When World War I broke out, he was sent to study at a Jewish high school in Vienna and then studied at art at the University of Vienna, and then taught at several Jewish schools in Vilna, Zamosc, Lwow, and Warsaw.
Split into simpler sentences: When World War I broke out, he was sent to study at a Jewish high school in Vienna. Later he studied at art at the University of Vienna and taught at several Jewish schools in Vilna, Zamosc, Lwow, and Warsaw.