Complex sentence: Dylan had moved to New York City to go to art school while Miller had started his own band called the 45's but after they broke up in 1989, he got in contact with Dylan again and they began forming The Apples.
Split into simpler sentences: Dylan had moved to New York City to go to art school while Miller had started his own band called the 45's. After they broke up in 1989, he got back in contact with Dylan and they began forming a new band called The Apples.