Complex sentence: In September 1941 he was assigned the post of an equipping officer of the brand new carrier "Zuikaku", where his job was to form the new air wing, himself becoming its leader when the ship was ready for duty.
Split into simpler sentences: In September 1941 he was assigned the post of an equipping officer of the brand new carrier "Zuikaku". His job was to form the new air wing, himself becoming its leader when the ship was ready for duty.