War of the Ring Q&A

so, im new to WOTR and want to get started. I find the game a lot like old fantasy, and love the aspects of it. But i have found some things that i cannot find in the rulebook. I understand (R) resilience, but how many wound counters does it take to kill a monster? i see a troll has 2(R), which means it has to take 2 hits to actually cause a wound counter. But, where i get confused is how many wound counters until it is removed from the game? that also goes with characters too.