Complex sentence: After the occupation of Poland, the Nazis separated the ghettos with ethnic Poles in the "Aryan side" and the Jews in the "Jewish side", any Pole from the Aryan side found assisting Jews in obtained food were subject to the death penalty.
Split into simpler sentences: After the occupation of Poland, the Nazis separated the ghettos, with ethnic Poles on the "Aryan side" and the Jews on the "Jewish side". Anyone from the Aryan side found assisting those on the Jewish side in obtaining food was subject to the death penalty.