1: Pour a known amount of black powder down the barrel, not so much that the resultant explosion exceeds the tolerances of the barrel, and not so little as to cause a "squib" (where there is not enough force to eject the projectile from the barrel).
2: Place the shot (the lead ball) at the mouth of the barrel (the shot will be slightly larger in dimensions than the barrel).
I: sometimes the shot may be wrapped in a "patch", usually lubricated cloth or paper, or a patch or wad (made of paper or cork) may be used separately before the shot.
3: Use a ram rod to force the shot down the barrel (if the barrel is rifled, this engraves the rifling to the shot) and seat the powder, with enough force to only slightly compress the powder.
4: Pull the cock to the half-cock position.
5: Open the frizzen (the lid over the priming pan) and add a small amount of powder to the pan, then close the pan.
I: this is called "primed and loaded", and is how the firearm would be carried for near-immediate use.
6: Pull the cock to the full-cock position.
7: The firearm is now ready to fire by pulling the trigger.
I: pulling the trigger releases a sear that allows the cock to fall.
II: the cock holds a piece of flint, that strikes the frizzen, opening it and causing a shower of sparks to hit the powder in the pan.
III: the powder in the pan ignites, sending sparks and hot ash into the touch hole between the pan and the base of the barrel.
IV: this causes the powder in the barrel to ignite, increasing the pressure inside the barrel very quickly as expanding hot gases accumulate.
V: the sudden increased pressure projects the shot out of the barrel at high speed.
