Complex sentence: Rodger then did his military training and left Royal Military Academy Sandhurst in 1940 and painted as part of the War Artists Advisory Committee (WAAC) during World War II alongside numerous other war artists.
Split into simpler sentences: Rodger then did his military training and left Royal Military Academy Sandhurst in 1940. He painted as part of the War Artists Advisory Committee (WAAC) during World War II, alongside numerous other war artists.