Complex sentence: He left Toronto in the late 1970s, when he was 20, to return to Europe and started making money as a busker and also found work at festivals as a blues lapslide guitarist and songwriter.
Split into simpler sentences: He left Toronto when he was 20 to return to Europe and started making money as a busker. It was the late 1970s by then, and he found work at festivals as a blues lapslide guitarist and songwriter.