Complex sentence: In 1924 and Orff founded the Günther School for gymnastics, music, and dance in Munich, where he was from 1925 until the end of his life the head of a department and where he worked with musical beginners.
Split into simpler sentences: In 1924 and Orff founded the Günther School for gymnastics, music, and dance in Munich. Orff was there as the head of a department from 1925 until the end of his life, and he worked with musical beginners.