There are numerous commercially sold dvds on building muzzleloader from those of Hershel to Ron Ehlert’s series (was available through Jim Chambers) to Peter Alexander’s multi-dvd series and finally to Mike Miller’s great series. Those are all great references but they also cost money. On the other hand beck when I started with my first muzzleloader, there was only one good book and it was William Buchele’s Recreating the American Longrifle available to us. There were no videos or even audio sources to learn from. Now we have these numerous commercial videos that as Cody I think said, if you just study and practice with one, you may hamstring yourself and miss another technique that fits your talents, tools and abilities better.
That said, there are also several very good learning sources online now that are led by Bill Raby’s multiple series of rifle builds on Rumble, then there is The Grumpy Gunsmith of Williamsburg with Clay Smith, then a number of them on the NMLRA website and other lesser know makers on YouTube such as Homemade History and several others. Additionally, Mike Brooks has a very good build tutorial on this website and you can even print it off and have a book for reference.
I am amazed today at all the reference sources, tools and video sources for learning and building muzzleloader. You guys starting out these days are very blessed to have all the learning sources at your disposal. Good luck and enjoy the study, learning and building fun!