You may have already talked to / passed by them, but PPH3 being hidden somewhere in the woods means that we need to find someone with navigation skills to help us find it.
This is the low-spoiler guide for "Finding an exploration expert" puzzle in Dexter Stardust: Adventures in Outer Space. 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.