David: there are countless threads in the "Black Powder Shooting" forum on loads, involving ball size, patch quality and thickness, and lubrication for them, powder granulation and quantity. But I agree, there is likely none that takes a new shooter and starts them off. Far better than reading the many and varied opinions of the rest of us, which can be intimidating and confusing as we argue about all these variables trying to make our points, is to find a mentor - someone who has some experience, and get them to start you off. And even then, there are parts of their process that you will want to experiment with and change, if you are serious about getting the most out of your equipment. So if you belong to a Gun Club nearby, there will be someone in it that has some experience. Flush them out and ask for guidance.
In the meantime, here's a start for you.
You will need a quantity of black powder - not substitute BP like Triple 7 or Pyrodex. Your powder for your rifles can be either 3Fg or 2Fg. The 3Fg is finer, will generate higher pressure and velocity for a given charge compared to the courser 2Fg. Personally, I use 2Fgin rifles over 45 cal. You need a powder measure and an adjustable one is useful when starting out as you will want to try various charges. Start with around 60 gr. You will need some patch material, and a means to measure its thickness, ie: a micrometer or Vernier's Calipers. The material needs to be 100% natural fabric, like cotton denim, hemp canvas, or linen, and be in the neighbourhood of .020" thick when measured by squeezing the cloth tightly within the jaws. You measure by crushing the fabric because that's what happens to it in the bore of your rifle, and the philosophy is to have enough thickness of patch to do two things: seal the bore with some compression to the bottoms of the grooves, and carry enough lube to soften and carry the fouling from the previous shot down to the powder charge with each new loading. I and those who subscribe to this kind of loading technique find it useful to use a starter - a knob of wood or antler about the size of a small lemon with a hickory rod coming from one side about 6" long. On an adjacent side of the knob, set a short peg (I use brass) which is placed on top of the ball and patch, and with a sharp smack drives the patched ball into the muzzle of the rifle. Once the ball is in the bore, it is easy to send it down with the longer peg. Now your bore acts as a guide so you can push the patched ball down onto the powder charge. I do not try to do this with pressure alone on the rod, which will likely eventually break your ramrod. Instead, raise the rod a few inches above the ball, gripping the rod about 6 - 8" above the muzzle, and then with a jabbing stroke send the ball down until your hand lands on the muzzle. Grip the rod another 6 - 8" above the muzzle and repeat, until the ball is all the way down firmly on the powder. It's a good idea to mark your rod (I use a Sharpie) so you know when it's down. There will come a time when you think it's down because the rod comes to an abrupt stop. Unless you have marked your rod you cannot be sure that you've reached the powder. If you fire your rifle without seating the ball on the powder, you run the risk of ruining your rifle in the least, and having it explode, in the worst. A ball in the bore not seated on the powder acts as an obstruction rather than a projectile, and will cause a pressure spike when the charge goes off that can cause serious consequences. Read that last sentence again...it is vitally important.
Once the ball is seated, return the ramrod to it's place on the rifle. A little note about that: your rifle may shoot to a different point with the rod in or out of the rifle, so return it every time.
Now, with the rifle pointed in a safe direction and you standing at the firing line, prime the pan of the lock with a small quantity of powder, either from your powder horn or from a priming device or horn carrying finer powder. I use a priming horn carrying FFFFg.
You are ready to shoot. Bring the cock back to full cock, raise the rifle to your eye, sight down the barrel aligning the sights on the target, and squeeze the trigger. Be sure to carry-through, ie: continue to aim at the target right through the shot. There will be a nuclear mushroom cloud right in front of your face as the priming ignites in the pan and sends a jet of flame through the vent into the powder charge in the barrel. Knowing this is about to happen will cause you to slam your eyes shup, pull your head away from the stock, in other words, flinch. And you will miss the target. So, fight through all of that, and follow through, aiming right through the event, and your ball will go true and take the centre out of the bull.
There is much more to this than I have described, and others will add to and refute this, so stay tuned and take away as much of this as you can use.
Good Luck David.
