Great advice on this forum. Welcome.

Read your manual and also run through some of the previous threads on this forum for some starter advice. If you go to a gun club, there will be people there more then happy to help.

For me personally, I like the easy of pellets rather then powder. However, I am limited with pellets in regards to tweaking my load for the greatest accuracy.
Everyone seems to start with a load of around 90 - 100 grains of commercial black powder or black powder substitue and a 250 grain bullet. I used the shockwaves starting out as they were cheaper and I wanted to practice quite a bit. For me, this was a good starting point and practice & tweak, practice & tweak, practice & tweak.

Get a decent scope. A couple have been mentioned already. Nothing is mre frustrating then to keep shooting only to find a cheap scope will not hold its zero.

Biggest piece of advice: Keep everything consistent (cleaning technique, powder amount, clean vs dirty barrel, # of swabs between shots, etc...) from shot to shot. Once you have established a consistent Point of Impact (POI), you can change one variable at a time and know exactly what that change did to the POI. If you run into anything, let us know.