Are you asking about how you reinvent the exact same meter? Well that won’t happen. Our units were arbitrary, useful, widely adopted, and then rigorously defined.
The book walks you through it all. You can don’t need to redo civilization exactly the same (the author even suggests some very important things to invent differently, especially in better orders)
That’s a fair point. Most likely if a group of people did some kind of Long Term Naked & Afraid experiment they’d just start with some length of particularly well-crafted cordage, call it a New Meter™ and go from there