Posting a pic might get you some basic info. However, if you are so green as to not know what you have and how to operate it, then you are only going to get yourself into trouble. Blackpowders are very specific about how to use them, and they can be more dangerous than a modern firearm if you don't know what you are doing. Regular gunpowder burns, but blackpowder is explosive, and there is a great difference between these two.

You would be better off trying to find first-hand information locally. Find someone willing to show you what kind of powder to use, and how to protect yourself from accidental ignition, which is especially important if your handgun has a cylinder. You are also going to need to size the bore correctly. Hopefully it is a caliber that is easily found....

Thanks for the info. I'll do that