Complex sentence: He started to live in the United States in 1981, first at the home of mentor and friend Wojtek Fibak; later, in 1984, Lendl bought his own residence in Greenwich, Connecticut.
Split into simpler sentences: He started to live in the United States in 1981, first at the home of mentor and friend, Wojtek Fibak. Later (in 1984) Lendl bought his own residence in Greenwich, Connecticut.