DESC: Your kind have more than one head granting an additional save per extra head to effects like blind, confusion, charm, dazed, distracted, fear, sleep, stun and suffocation.
During combat each head can attack on your combat round only if you purchase the synchronize value that is equal to the number of additional heads you have, one additional head is assumed. Each head will have access to any head or mouth based powers such as Breath Weapon, Bite, Gaze and so on. Each head can only activate one power at a time though and they can activate the same or a different power. For example one head can breath fire and a second can bite if the creature has these powers.
The order of the attacks of each head is always what is best for the creature based on what it knows during the combat. If the first head breaths fire at a target that is immune then the second head can instead bite, or breath acid if those are options.