When you get Brother Lightbeard's cloud down the next thing is to ask F'thr to untie the bow. Give him any good reason to help you (not the fraudster one).
This is the low-spoiler guide for "How to untie the knot?" puzzle in Broken Age. Unlike in normal walkthrough, you get gradual hints on how to solve the puzzle. Click the big button below to see your first hint. If the hint contains a spoiler, you will be warned about it before clicking.