Complex sentence: He worked at decorative painting jobs in Moravia, mostly painting theatrical scenery, then in 1879 moved to Vienna to work for a leading Viennese theatrical design company, while informally furthering his artistic education.
Split into simpler sentences: He worked at decorative painting jobs in Moravia, mostly painting theatrical scenery. In 1879 he moved to Vienna to work for a leading Viennese theatrical design company, while informally furthering his artistic education.