This is how this works. It's three basic components.
The firelock, which is the working mechanism,
the wooden stock and the barrel which can
be changed around if you need to replace a
part - so if you've heard the phrase of purchasing
something "lock stock and barrel" that is
where it comes from.
Now, there is a drill that comes from the
1764 British army field manual - the minutemen
and the militia would have been using this
manual to train - they would want to be as
good as their potential opponents, so they are using the same playbook.
That involves 14 steps to prime, load and
fire the weapon. What that involves, and you
will see that in just a minute, is that I take
a cartridge from my cartridge box (a rolled
paper tube with a pre-measured amount of gunpowder
in it), it would have a musket ball in the bottom of it,
but of course, we are not firing musket balls today....
I would tear this off with my teeth, and pour
a little of this powder in this pan right
next to the barrel and shut it. Everything
else goes down the barrel, the rest of the powder, the
ball and the paper to serve as a wadding to keep it all down there.
Then you need to take out your ramrod and
ram that down - one easy motion is all you
need.
It's very important that you put the ramrod
back.
Right here, this is called the cock. It has
a piece of flint in it.
So, when I'm ready to fire this, I pull this
all the way back - to cock the gun (that is
where that phrase comes from). I pull the
trigger, this comes flying forward, the flint
hits the steel creating sparks and at the
same time opening the steel so that the sparks
drop in the pan. The first explosion will
be sucked into a tiny hole in the barrel setting
off the main charge.
Take care, press your firelock.
Shoulder your firelock.
Prepare to prime and load.
Handle cartridge.
Prime.
Shut pan.
Cast about.
Charge with cartridge.
Draw rammer.
Ram down cartridge.
Trim rammer.
Shoulder firelock.
Make ready.
Present. 
(Cover up your ears.)
Fire!
