Complex sentence: On 21 April, during the Battle for Berlin, Steiner was placed in command of Army Detachment Steiner, while (Adolf Hitler) ordered Steiner to envelop the 1st Belorussian Front through a pincer movement, advancing from north of Berlin.
Split into simpler sentences: On 21 April, during the Battle for Berlin, Steiner was placed in command of Army Detachment Steiner. Hitler gave orders for Steiner's forces to envelop the 1st Belorussian Front through a pincer movement, advancing from north of Berlin.