I dont know if this is approriate but i will tell you the simplest form of making black power(gunpowder)
A normal black powder contains 3 main ingredients
*pottasium nitrate 75%
*charcoal 15%
*sulphur 10%
*i will show you some household items you need and method in making/getting it.
On my next thread we shall know how to make a simple single shot gun. Because the black powder is as useless without a gun.

DISCLAIMER- You are responsible for any damage and what you use this thing for.