The Macedonians, as the invaders, went first rolling average PIPs. Alexander's wing advanced (including the Hypaspidists), and followed by the centre and Parmenio's brave Greek mercenary cavalry. The Macedonians had much better command and control because they had 4 regular commands that were fairly close to each other (Luke had included a scenario special rule that regular generals could only swap PIP dice if within 1800p). The Persians on the other hand effectively had an irregular command structure for most of the battle as they only had 3 commands and their generals started deployed very far apart.