Complex sentence: He was selected to become an officer and posted to the SS-Junkerschule at Bad Tölz from 1936 to 1937 after graduation he was promoted to Untersturmführer (Second Lieutenant).
Split into simpler sentences: He was selected to become an officer and was posted to the SS-Junkerschule at Bad Tölz from 1936 to 1937. Following graduation, he was promoted to Untersturmführer (Second Lieutenant).