Complex sentence: Lui's business career first took form in the 1980s, during four years at upstart Mrs. Fields Cookies where he lead the company's largest sales unit and management training center at the age of 18.
Split into simpler sentences: Lui's business career first took form in the 1980s. During four years at upstart Mrs. Fields Cookies he lead the company's largest sales unit and management training center at the age of 18.