Complex sentence: Then, at 18 he received his "break" of sorts when, at a Donna Karan Party with his father, he introduced himself as a DJ to party planner Jeanette Calliva, who had begun putting on nights at Chinawhite.
Split into simpler sentences: Then, at 18, he received his "break" of sorts. At a Donna Karan Party with his father, he introduced himself as a DJ to party planner Jeanette Calliva who had begun putting on nights at Chinawhite.