Complex sentence: The Buckaroos were a Grammy-winning backup band for lead artist Buck Owens in the 1960s, who were heavily involved in Owens' development and presentation of the "Bakersfield Sound".
Split into simpler sentences: The Buckaroos were a backup band for lead artist Buck Owens in the 1960s. They were heavily involved in Owens' development and presentation of the "Bakersfield Sound".