how to start
well yes percussion is easier and more reliable.
So your main thing is which to start with
pistol / revolver ot rifle.
Pistols technically is a single shot and a revolver 5 or 6 shots.
If you are handy with your hands, filing sanding etc, nothing wrong with a kit.
Done a lot of them to save money and something to do watching the boob tube.
Course after you get the gun, you will need balls, patches / wads, caps, powder a flask and a powder measure.
and then the fun begins as you get addicted.