Complex sentence: Mitty was admitted to the Royal Military Academy Sandhurst for officer training in 1942, following which he was commissioned as a second lieutenant in the Army's Hampshire Regiment and was sent to East Asia.
Split into simpler sentences: Mitty was admitted to the Royal Military Academy Sandhurst for officer training in 1942. Following his training, Mitty was commissioned as a second lieutenant in the army's Hampshire Regiment and was sent to East Asia.