MosinMan13 : Follow vagrantviking's suggestions.
Use a bp-compatible lube(non petroleum based). With a suitable bullet. The bigger and more lube grooves, the better.
Note: Look up "big lube" bullets. May offer some idea what sort of bullet to look for. Also: the more grooves, the better. More lube capacity.
As already mentioned, check the end of the muzzle, after firing. There should be a noticeable "star" of lube left behind. This is a good indicator that you're using the right lube. Plus enough lube. If not seeing that soft, waxy lube build up after a few shots....or....getting a lot of hard fouling....you are either using too little lube. Or, the wrong lube.
Caveat: Avoid commercially available bullets intended for smokeless powder use. The lube used is often too hard to soften black powder fouling...resulting in hard, caked on residue after a few shots. The lube is easily removed by gently heating the bullets and wiping off the lube. Then, pan dip or lubri-size the bullets again. This time, with a bp-friendly lube. *
As far as cleaning the bore every so often...one of the best bore cleaners I've ever used, is ordinary isopropyl alcohol(rubbing alcohol. Can buy it just about anywhere....pharmacy, etc. One wet patch, followed by a couple of dry ones and the bore is squeaky clean again.
Another good product: Ballistol. Often referred to as the "Black powder shooter's best friend". Can be used either in straight form as a lubricant. Or diluted, as a bore cleaner. Works very well. Ballistol is mineral-oil based, so fully compatible with bp.
Ballistol is readily available at your local Canadian Tire, hardware, etc. In either spray, or liquid form. Or, can be ordered factory-direct.
As far as how often to clean: Frequently! After every few shots, if necessary. Don't wait for fouling to build up. The cleaner the bore remains, the more consistent accuracy and performance. Plus: Far less(or no) leading.
Hopefully, this answers some of your questions.
Al
ps: * You can easily make your own bp compatible lube, with a couple of simple ingredients: Tallow(Any tallow works). Plus: Beeswax (Not paraffin!). For some good information on how to make your own lube(and lubricated wads)...go to the duelist1954 you tube site. Hosted by well known black powder expert: Mike Beliveau.
May have to back a bit on the play list, but featured there are a couple of highly informative videos on the process. Worth a look.
Or, you can purchase commercially-made lube. SPG, is excellent.