Complex sentence: Beatty's coaching career began in 1978, when he began working as an assistant coach and teacher at Clinton High School in Clinton, Missouri, where he stayed for two years until he moved to William Jewell College.
Split into simpler sentences: Beatty's Coaching Career began in 1978, when he accepted a job as an Assistant Coach at Clinton High School in Clinton, Missouri. He stayed at the position for two years, until he moved to William Jewell College.