Complex sentence: Thomas William Hamilton first started playing guitar when his brother (scott) taught him his first chords when he was 12 and switched to bass when he was 14 to join a local band because they had an open space at that position.
Split into simpler sentences: Thomas William Hamilton first started playing guitar when his older brother Scott taught him his first chords at age 12. Tom switched to bass when he was 14 to join a local band because they had an open space at that position.