There are a few ways of manufacturing tinder (amadou) from the Fomes Fomentarius this is but one. Many would-be alchemists will add in all sorts of things, urine, saltpetre etc try this yourself as it's all about experimentation.
You will find this hoof fungi growing on birch.
Once gathered you need to strip out the layer between the outer case and the woody pores, the remains can be added to the fire so as not to waste it.
Add in some hardwood ash and boil up for around 24 hours on the camp fire. You then can get on with other projects.
This is what you will end up with.
Place on log and flatten with wooden baton.
Flattened out trama layer.
It will then resemble slithers of jerky beef. Leave to dry.
Once dry it resembles chamois leather.
Fluff up surface with flint.
Strike with steel in a downward direction with the tinder on top of the flint.
You now have a smouldering ember for the production of fire.