There are several videos on gun building on the Kempton Gunmakers fair, YouTube channel. These videos are a very small sample of the information available, each day, at the seminars at the gunmakers fair. There are also quite a few good building DVDs available at the Log Cabin Shop, and I second Bill Raby's videos on Rumble. There are also several other, on line, videos about gun building, however, some of the people who post those videos are not well versed in gun building, others are.
For someone who has little to no machinery, you might check out Curtis's thread, on this site, for building a Hawken Rifle.
I also recommend buying a few DVDs, or thumb drives of, very well done, very detailed, photographs of original longrifles from the Kentucky Rifle Association. The gunmakers fair is also an excellent place to see and, often, handle original longrifles.
There are several dealers selling gun stock blanks, who will inlet the barrel and drill the ramrod channel in PA. I received a nice stock blank, today, with a very well done, barrel and ramrod inlet from Mark Wheland, from Williamsburg PA, and Knob Mountain is in Berwick, for example.
https://www.youtube.com/@GunmakersFairatKemptonGood luck and have fun learning the skills to support this, often frustrating, and very satisfying hobby.
J.D.