Complex sentence: He was selected to become an officer and posted to the SS-Junkerschule in 1937, and upon graduation was promoted to Untersturmführer (Second Lieutenant) in March 1938 and posted to the Leibstandarte SS "Adolf Hitler" Regiment.
Split into simpler sentences: He was selected to become an officer and posted to the SS-Junkerschule in 1937. Upon graduation in March 1938, he was promoted to Untersturmführer (Second Lieutenant) and posted to the Leibstandarte SS "Adolf Hitler" Regiment.