Complex sentence: During his time in college, he worked as a bouncer at the age of 19, at one of Chicago's hottest clubs, Shelter, where he learned the ropes of the nightlife industry.
Split into simpler sentences: During his time in college, he worked as a bouncer at the age of 19, at one of Chicago's hottest clubs, Shelter. It was there that he learned the ropes of the nightlife industry.