[ghaff]

A fire steel is probably the simplest low-tech way to start a fire. You still need some expertise like finding a mouse nest or other flammable material even if it's been reasonably dry.

But friction methods are tough, even if you have a well-made spindle and fireboard--which of course require tools. You're not easily creating those without tools to make those tools. And, even then, it's not super easy especially in a non-optimum environment.