Complex sentence: Kempka followed Hitler to the Reich Chancellery in 1945, and briefly wished the Führer "Happy Birthday" on April 20, spending about 15 minutes in the bunker with him that day.
Split into simpler sentences: Kempka followed Hitler to the Reich Chancellery in 1945. He briefly wished the Führer "Happy Birthday" on April 20, spending about 15 minutes in the bunker with him that day.