Complex sentence: The duo begun to produce music videos to promote their records; in early 1975, they filmed a performance of "Please Mr. Postman" at Disneyland and "Only Yesterday" at the Huntington Gardens.
Split into simpler sentences: The duo begun to produce music videos to promote their records. In early 1975, they filmed a performance of "Please Mr. Postman" at Disneyland and "Only Yesterday" at the Huntington Gardens.