Complex sentence: Close began his military career in 1974 as an Infantry Battalion Commander (Lieutenant Colonel) of the 25th Infantry Division in Hawaii after being transferred to Washington, D.C. to be a Senior Aide-de-Camp to the Secretary of the Army.
Split into simpler sentences: Close began his military career in 1974 as an infantry battalion commander (Lieutenant Colonel) of the 25th Infantry Division in Hawaii. He was later transferred to Washington, D.C. to be a senior "aide-de-camp" to the Secretary of the Army.