Complex sentence: It is a loose concept album which tells the story of Bowie's alter ego Ziggy Stardust, a fictional rock star who acts as a messenger for extraterrestrial beings.
Split into simpler sentences: It is a loose concept album which tells the story of a fictional rock star named Ziggy Stardust. The album tells the story of Bowie's alter ego Ziggy Stardust, a rock star who acts as a messenger for extraterrestrial beings.