Complex sentence: Eventually he directed the army to establish a line centered in Pfullendorf, where he planned to engage the Austrian army under the Habsburg commander in chief Archduke Charles on the Ostrach plateau.
Split into simpler sentences: Eventually he directed the army to establish a line centered in Pfullendorf. He planned to engage the Austrian army under the Habsburg commander-in-chief Archduke Charles on the Ostrach plateau.