Complex sentence: At school he was fond of painting and after the 8th grade left it to join the Mikhail Kalinin Art college where, after meeting a member of a youth puppet theatre/studio Globus, he got interested in theater.
Split into simpler sentences: At school he was fond of painting and after the 8th grade left it to join the Mikhail Kalinin Art college. After meeting member of a youth puppet theatre/studio Globus, Bogatyryov got interested in theater.