Complex sentence: Guests chosen to appear on the show were booked airfare to New York City, brought to the television studio and sent to specific "green rooms", inside which they were briefed in more detail on how the show would be taped.
Split into simpler sentences: Guests chosen to appear on the show were booked airfare to New York City. The guests were brought to the television studio and sent to specific "green rooms", inside which they were briefed in more detail on how the show would be taped.