Complex sentence: The Cotton Club first opened in 1923 in Harlem on the 2nd floor of a building at 142nd Street and Lenox Avenue in a space formerly leased and operated by Jack Johnson, the boxer, as the Club Delux, an intimate supper club.
Split into simpler sentences: The Cotton Club first opened in 1923 in Harlem on the 2nd floor of a building at 142nd Street and Lenox Avenue. The space had been formerly leased and operated by Jack Johnson, the boxer, as the Club Delux, an intimate supper club.