Complex sentence: Beginning before first light on 9 August, 5 RAR sealed off Binh Ba under cover of darkness to maintain surprise, supported by two companies from 6 RAR as well as APCs, engineers and artillery.
Split into simpler sentences: Beginning before first light on 9 August, 5 RAR moved to seal off Binh Ba under darkness to maintain surprise. In support were two companies from 6 RAR as well as APCs, engineers and artillery.