It's been a while since I've played Overlord.
A Field General who receives a Tactic card may never receive or play any other Command card during the same turn.
Likewise, a Commander-in-Chief who plays a Tactic card directly can never play another Command card during the same turn (though he may still give two other Command cards to his Field Generals).
Based on this, the CinC can only play 1 Barrage (a Tactic card with a commander symbol on it) per turn, plus up to 2 Section cards to the other generals. A general that doesn't receive a card can roll for initiative.