Let me be the second to welcome you to Greybeard Outdoors. All of us shooters started same as you, since black powder muzzle loading is not a topic taught in school.............................................yet.
You do not need anything between your powder and your conical when shooting with black powder though many shooters use this or that to improve accuracy.
One way I learned a bit about shooting black powder was to take my rifle, powder, and ball to a range where black powder was being shot. Next best thing for a muzzle loading shooter besides shooting, is talking to some one about shooting muzzle loaders.
Once you learn how to shoot patched round ball, then you can experiment with ugh! different type powders, and ech! various bullet styles. You might want to try a vous(Rendezvous) someday, or get into some other informal black powder competition. And don't forget the special seasons set aside for muzzle loading hunters.
It is a great sport, this black powder shooting, I wish you the best times while enjoying it.
Crow_feather