Hand to Hand and Multiple Attacks

I had a brain fart... reading the rules, if you stun/knock down a model in HtH, you can not then take them OOA on the same round. That is why multiple units are needed to attack a model.

So, with a troll and 3 attacks, if I stun/knock down a model with my first attack, are my other 2 attacks wasted? Or do I simply roll to hit/wound as needed on each extra attack?

Seriously, I should know this, but I am drawing a blank.

You have to declare how many attacks you dedicate to one opponent. So, if your troll only fights one, all attacks are rolled against him at the same time. Those which hit are then rolled for to wound, and for each wound caused, you roll once on the injury chart, applying the highest result. The same goes, as far as I know, for causing two wounds with a critical hit.

yearh what E. said. declare up front

What was stated above is 100% correct.

Just to clarify: the additional attacks aren't wasted, because you roll once on the injury table for each successful wound. Thus, if your first wounding attack knocks down the opponent, the second wounding attack has a chance to stun or OOA the opponent. As all of a model's attacks are rolled simultaneously (except in odd cases such as a saurus's bite), this should not really be an issue as there isn't really a 1st, 2nd, 3rd... attack. Rather, all would hit, wound, and injure simultaneously.

We house-rule that extra attacks can be used to take out stunned opponents.