Triggeraction params are like gani aparms almost. ITs all string based so if you wanted a triggeraction to hit a person for like 1 damage (Would make more sence with hitobjects though) then...
NPC Code:
triggeraction targetx,targety,hitperson,1;
and the other person must have a weapon with contains
NPC Code:
if(actionhitperson) {
hurt strtofloat(#p(0));
}