I have not used it before. But between people on this site and a little bit of reading elsewhere I was able to put my package together pretty painlessly. The package requirements and paperwork at the start isn't the hard part though, the hard part is wading through the WA state and federal code to prevent any mistakes.
-WA state requires a UBI so you will need to file with the state for a business license even if your city does not require one for sole proprietorships.
-Check your zoning and file any necessary paperwork with the city/county. Call the city/counting zoning commission, most of them are more than willing to help.
-Fill out Forms 5310, 5330, and get your finger print cards done.
-Get passport pictures.
-Submit. Send a copy to your local PD, or Sheriff depending on where you are.
-Wait impatiently for a month or longer for a response.
-IOI interview
-WA state Firearms Dealer License.
-Wait some more.
-Business.
viewtopic.php?p=651057#p651057 - This response from 3584ELK is invaluable between the time you drop your package and are waiting for your IOI interview.