Playing the single player mode is a great idea, especially through the missions where you have to capture beasts. "Capturing" is an important skill to learn, and nothing makes you look like an awful player online like picking up a trap in the supply box and immediately setting it down on the ground. If no one has materials, the mission is pretty much failed.

Three steps for trapping:

(1) Weaken the monster until it is limping,

(2) drop a trap either in a path where it will go or while it is sleeping,

(3) hit it a bunch of times with tranq bombs/tranq bullets until you get mission complete. Stronger monsters (meaning both less damaged/more powerful) need more tranq shots.