Complex sentence: Producer David Merrick employed Merrill to write additional songs for the musical "Hello, Dolly"/Merrill contributed two songs, "Motherhood March" and "Elegance", and some additional lyrics to Jerry Herman's It Takes a Woman.
Split into simpler sentences: Producer David Merrick employed Merrill to write additional songs for the musical Hello, Dolly. His contributions amounted to two songs, Motherhood March and Elegance, and some additional lyrics to Jerry Herman's It Takes a Woman.