Complex sentence: Between 1923 and 1924, he trained as an artillery officer, was promoted to "Oberleutnant" in 1925, and assigned as a battery commander in the 4th Artillery Regiment.
Split into simpler sentences: Between 1923 and 1924, he trained as an artillery officer. Promoted to "Oberleutnant" in 1925 and assigned as a battery commander in 4th Artillery Regiment.