Complex sentence: He started working at a Chicago's local printing house, soon he started attending Wheaton College (Illinois), founded his own print house, bookstore became publisher, writer and editor of his newspaper "Hrvatski glasnik".
Split into simpler sentences: He started working at a Chicago's local printing house before attending Wheaton College (Illinois). He later founded his own print house and bookstore, and became publisher, writer and editor of his newspaper "Hrvatski glasnik".