Complex sentence: Bill Ham was a record promo man for Bud Dailey Distributing when he saw the Sidewalks perform at a Doors concert in Houston and came backstage to tell the band how impressed he was.
Split into simpler sentences: Bill Ham was a record promo man for Bud Dailey Distributing. Ham had seen the Sidewalks perform at the Doors concert in Houston and came backstage to tell the band how impressed he was.