Complex sentence: He volunteered for the Army in 1943, and having trained at Sandhurst and Bovington, was commissioned into the 7th Queen's Own Hussars on 19 April 1946.
Split into simpler sentences: He volunteered for the Army in 1943, and was trained at Sandhurst and Bovington. He was commissioned into the 7th Queen's Own Hussars on 19 April 1946.