If you contact the Muzzle Loaders Association of Great Britain which is based in the Midlands they have an excellent book (The Modern Muzzle Loader) for about £6 which explains darn near everything about the sport and a bit more.
Here is the link for the pistol section http://mlagb.com/pistol/index.htm
Here is the link for the book http://mlagb.com/supplies/index.htm
Best gun to get for a newby is a Ruger Old Army .45 (thats a .45 not a .44 - important to remember when applying for an FAC or variation) which is a stainless steel modern version of the blackpowder revolverl, very nice guns and extremely accurate. It is not allowed in alot of the competitions except the Free Pistol, but you can learn alot from it and it is a massive revolver you will enjoy immensely. Expect alot of cleaning and faffing about with grease, it is a rather dirty occupation but with lots of explosions and flames! You'll love it.
I am saving it for my retirement (if it is still legal).