Looks like a chunky plate/disc growing out the side of a tree.
Break this off the tree and hold a red-hot ember against the spongy inner flesh. Once you have a glowing red ember in the tinder fungus, this can be loosely wrapped in moss and placed in a backpack. This ember will smolder for hours, just remove it every hour or so, and gently blow on it to keep the ember alive.
This popular method used by many indigenous tribes, wraps hot coals in a layer of Moss, Green Sticks and Tree Bark (in that order) and then gets firmly bound and tied. You want to make sure that your package is bound tightly enough to carry, without being bound too tightly. The idea is to semi-starve the embers of oxygen without suffocating them.
The same method is as the ember bundle is applied, only the embers are packed in charcoal before being wrapped in Moss and carried in a ventilated tin with a handle. Hardwood embers work best for both the Ember Bundle and Ember Box.