Tannerite has been providing a mixing container as of late. If you don't get one, you can use a ziplock bag to mix in and break up the clumps, if you wish. It does need to be mixed well. It's pretty hard to do that in the bottle, but it can be done. You may have to tap the bottle when half full to get the rest of the mixture in, if mixing in a seperate container and filling the bottle with a funnel.
As beekeeper said, it is one level Tablespoon of the grey/silver sensitizer powder per bottle. A measuring tablespoon, or a slightly heaping dinner tablespoon are about the same.
To give you an idea of how loud it is, my neighbors nicely asked me to stop setting it off at the house, and I have 30 acres. Now I call them on New Year's and 4th of July and let them know I am going to set some off.