In combat, we are alternating attacker defender. I have several questions
1. When my defender unit has pistol damage it can attack a unit, a focus attack can follow rules, but how does it do blast damage, am i supposed to declare an objective target AS A DEFENDER?
2. If we are alternating resolving cards and I do tactics damage to a card that has NOT attacked yet, do I block his attack turn on that card? if so couldnt i do that to a bunch of cards at once????
1. When defending, Unit Damage icons and Tactics icons resolve normally. Blast Damage icons do not resolve. See page 21
2. Yes, your Tactics icon would resolve and you would place one focus token onto a target enemy unit. If the unit is in the engagement, that would keep it from being able to strike back, as it is now exhausted. If your attacking unit had more than one enabled Tactics icon, you would do this once for each icon. Note also that the target unit does NOT have to be in the engagement - your Focus token could be placed on any enemy unit in play. You could also place focus tokens on units that are already exhausted, thus piling on extra tokens and keeping the unit effectively out of play for more than one turn, since only one token can be removed during the Refresh phase (barring other effects or the Elite keyword).
See page 21 under "Tactics" and "Blast Damage" for further clarification.