How do you capture a monster in Monster Hunter Freedom Unite

you can only capture a boss and to do that you fight the boss until it shows a sign of weakness (leg limping) that will let u know that it's ready for capture. Get a shock trap and trap it and when it's trapped throw some tranq bombs at it and it shoul fall asleep after 2 or maybe 3.

A good way to know when to capture it is to have the skill Tranq Guru where it allows you to know when exactly to throw the bombs at it. The monster will turn yellow when ready.