Complex sentence: On 16 September, in order to achieve their objective, the corps ordered its units to advance with the main axis of the attack directed at Vodice and supporting advances directed towards Zadar, Drniš and Sinj.
Split into simpler sentences: On 16 September, in order to achieve their objective, the corps ordered its units to advance. Their main axis of the attack directed at Vodice and supporting advances directed towards Zadar, Drniš and Sinj.