Complex sentence: Colston was born in Brisbane, and joined the Labor Party at the age of 19 holding several branch positions in the party before unsuccessfully nominating for selection as a Senate candidate at the age of 23.
Split into simpler sentences: Colston was born in Brisbane and joined the Labor Party at the age of 19 and held several branch positions in the party. He was unsuccessfully nominated for selection as a Senate candidate at the age of 23.