Complex sentence: At the beginning of the episode, Jack and Liz are at a jewelry store, in which Jack is searching for an engagement ring for Elisa, was filmed at a Cartier store located in New York's Fifth Avenue on February 22,2009.
Split into simpler sentences: At the beginning of the episode, Jack and Liz are at a jewelry store, as Jack is searching for an engagement ring for Elisa. They shot that scene in a Cartier store in New York's Fifth Avenue, which was filmed on February 22,2009.