Two ATF Form 1s signed by you local Chief LEO, Sheriff, Chief of Police etc. Don't know how TN does it. In Kaintuck, the Sheriff does everything, the po-po point in the general direction of the county court house and say "He does it". In Newport News it's the sheriff too.

2 sets fingerprints on correct ATF ori addressed cards. You can roll your own ( I did once and they passed) or have your local constabulary do it.

Passport sized and framed - doesn't have to be passport quality just size - color photos of you, no older than 1 year. (one glued to each form).
You can take them yourself, or if you're good at it, a digital pix can be printed directly on the form. Again, I did it once, just to see if it would fly and it did.

$200.00 check made out to ATF

Signed citizenship form (only one copy needed per firearm) certifying yourself to be a U.S. citizen.

6 month to 1 year wait.

Get approved form back

Whacken sie the barrel (please not before).

These are the high points.

Having dome the same, it's a pain in the buttocks.

I can get into more detail if you want to do it.