ensure gun is clean, ensure nipple is not plugged, you SHOULD get a powder measure, a capper, a good ramrod /fibreglas or other, a short starter , caps /powder ( pyrodex or real black powder 2f or 3f type, ) proper calls fer your calibre? patching material,
thats a start ....................................then maybe a powder horn, or possible bag, to put it all in most things can be made or obtained easily.
good luck.