This is a useful Dropbox link from Dave Stoddard, a famous pyro. He wrote up a Powerpoint that instructs you how to fill our an ATF Application. He also includes a copy of his Magazine spreadsheet, it shows the various types of data required to be kept for ATF inventory purposes. Also included are copies of the ATF Orange Book and variance letter.
Anyone planning on getting their Permit or License, feel free to reach out to me with any questions.