Complex sentence: After operating for five years as a distributor of imported products, Maruchan built its own manufacturing facility in Irvine, California and in 1977 began producing Maruchan brand ramen at the Irvine factory.
Split into simpler sentences: After operating for five years as a distributor of imported products, Maruchan built its own manufacturing facility in Irvine, California. By then (1977) began producing Maruchan brand ramen at the Irvine factory.