I'm in the same boat. After all of the modern including military stuff I've shot, I started to get interested in old, historic western firearms.
There are a couple of good YT vids that show about all you need to know.
This one is kinda long but he goes over loading pretty thoroughly. I plan to start off with the pelletized versus loose powder just for the convenience...plus you don't need to get a flask/measure right a way.
Personally, I'd take a look at the Uberti or Pietta 1858 (Remington) New Army replica. This particular firearm was widely used in the Civil War, was the last of the Remington black powder pistols, by virtue of having a top strap (as opposed to the Colt Walker and Dragoons for example) has the advantage of being stronger and, should you really get into it, it has easily exchanged cylinders (ala Clint Eastwood in Pale Rider). You can also get a conversion cylinder which allows you to shoot 45LC in it since the way the measured .44 back in the day was really a .45. Dixie Gun Works has the Uberti on sale for $285 and there's no FFL to fiddle with: it ships straight to your door.