Complex sentence: He was selected to become and officer and sent to the SS-Junkerschule in Bad Tölz in the class of 1938, after graduation he was promoted to Untersturmführer (Second Lieutenant).
Split into simpler sentences: He was selected to become an officer and was sent to the SS-Junkerschule in Bad Tölz in the class of 1938. After graduation he was promoted to Untersturmführer (Second Lieutenant).