All you do in soulwars is run around and attack players with the different colored cape. For example if you are on the red team, you get a red cape. Blue team, blue cape. So just attack the other teams players for 20 minutes and hope that the high leveled players on your team slayed the other teams NPC and you will get 3 zeal if your team wins. 2 Zeal if its a tie, and 1 zeal if your team loses.