Complex sentence: Holden started out with Liverpool youth, aged 6 but was released by the club at the age of 12, before joining Everton's youth team for eighteen months before moving to Tranmere Rovers as a trainee.
Split into simpler sentences: Holden started out with Liverpool youth, aged 6 but was released by the club at the age of 12. He joined Everton's youth teams for eighteen months before moving to Tranmere Rovers as a trainee.