Complex sentence: In the second half of the 1940's he served in three overseas posts; he was briefly attached to Douglas Macarthur's Tokyo, and he spent a long period of time in New Zealand, and then in India.
Split into simpler sentences: In the second half of the 1940's he served in three overseas posts. He was briefly attached to Douglas Macarthur's staff in Tokyo, Japan, but he spent a significant amount of time in New Zealand and then in India.