Complex sentence: He joined the South African Army as an artilleryman in 1924, and during World War II he commanded divisional artillery in East Africa and North Africa, before commanding an infantry brigade and an armoured brigade.
Split into simpler sentences: He joined the South African Army as an artilleryman in 1924. During World War II he commanded divisional artillery in East Africa and North Africa, before commanding an infantry brigade and an armoured brigade.