Complex sentence: Martin was the deputy commander of 36th Medical Group at Andersen, and the other crewmembers, were all from the 20th Bomb Squadron at Barksdale Air Force Base, Louisiana.
Split into simpler sentences: Martin was the deputy commander of 36th Medical Group at Andersen Air Force Base. The other crewmembers were all from the 20th Bomb Squadron based at Barksdale Air Force Base, Louisiana.