You've got the right idea, but you're missing one vital item. If you examined the troll, you would have noticed that he's wearing a pouch, but he won't let you take it. He's bigger and stronger than you, so you can't fight him. Once you get past the troll, he'll have his back to you. You can then take advantage of the situation and throw something heavy at him to knock him out.
Thank you for the kind comment. I'm glad you like them.