Complex sentence: He wrote and co-wrote many of their songs, including co-writing their well known chart topping song, "Down Under" and singing lead vocals on "Settle Down My Boy", one of his own songs from the Men at Work album, "Cargo".
Split into simpler sentences: He wrote and co-wrote many of their songs, including "Down Under". He sings lead vocals on "Settle Down My Boy", one of his own songs on the Men at Work album "Cargo".