The winning player may activate a single division or a corp commander who may activate all the divisions within his corp and with his command range. The basic order for a unit is to move, and combat occurs and is dependent on movement. The less you move to engage an enemy unit, the better prepared your unit is for battle and the better it will perform. Movement rates are based on a die roll for infantry and two dice for cavalry, with the Confederates getting a die roll bonus. The thing I love about this, is you're never sure you'll be able to get what you need when you need it.
Disrupted units are weaker in combat.
After the fourth move, the unit is spent and can no longer move except in retreat. A player can avoid this by 'passing' his move to his opponent, but if his opponent passes as well, the turn ends. The bigger the result spread between the die rolls, the greater the difference in effect on the combatants. From what little I've been exposed to, the system seems depressingly realistic. The terrain effects on combat make a re-enactment of the Confederate stand against Burnside at Sharpsburg very possible in game terms.