Complex sentence: Muqran served in several squadrons from 1973 to 1977 before being appointed the Adjutant to the Director of Air Operations, and, finally, the President of Operations and Planning for the Royal Saudi Air Force.
Split into simpler sentences: Muqran served in several squadrons from 1973 to 1977. He was appointed Adjutant to the Director of Air Operations, and then President of Operations and Planning for the Royal Saudi Air Force.