He then formed his own dispositions.

The army with which he was to attack above a million of men consisted of 40,300 foot and 7000 horse.

Alexander drew them up in three lines: The first consisted of light-armed troops, horse and foot, of good quality, which were especially intended to act against the enemy's chariots.

The next was the main line of battle, and contained the phalanx with the rest of the heavy infantry in the centre, the heavy cavalry upon the two wings.

The third line consisted of light troops, chiefly horse, and was instructed to act against such of the Persians as should outflank the Macedonian main line and so threaten their rear.
As at Issus, Alexander took the command of the right wing himself, and assigned the left to Parmenio.
As the two armies drew near, Alexander, who found himself greatly outflanked on both wings, and saw in front of him smooth ground carefully prepared for the operations of chariots and cavalry, began a diagonal movement towards the right, which tended at once to place him beyond the levelled ground, and to bring him in contact with his enemy's left wing rather than with his direct front.