Step 3: Use
Insert a 10 in. long fuse into the pile. (Instructions for fuse here http://www.instructables.com/id/E9ZBOE35P9EPA8KZXX/ )
Light and stand back. When the fuse ignites the flash powder a bright flash and pfft sound will be given off.
A large cloud of smoke will also be produced.
I know its hypocritical for me to say this but: Please be satisfied with that and do not make fireworks.
I have the experience to do these things safely, no matter how dangerous I make it seem in videos or photos. I know exact burning rates of all the fuse I use, proper amount's of powder to use, and proper containers to use, etc. So please don't try to make fireworks unless you know what you are doing.