Complex sentence: The band was founded by Randy Owen (lead vocals, rhythm guitar) and his cousin Teddy Gentry (bass guitar, background vocals), soon joined by their other cousin, Jeff Cook (lead guitar, fiddle, keyboards).
Split into simpler sentences: The band was founded by Randy Owen (lead vocals, rhythm guitar) and his cousin Teddy Gentry (bass guitar, background vocals). They were soon joined by their other cousin, Jeff Cook (lead guitar, fiddle, and keyboards).