Complex sentence: He began playing professionally in high school with Bubbles Becker, then played with Sonny Dunham in the 1940s before joining Ray Anthony in 1948-49 and again in 1951-52.
Split into simpler sentences: He began playing professionally in high school with Bubbles Becker. He then played with Sonny Dunham in the 1940s before joining Ray Anthony in 1948-49 and again in 1951-52.