Assuming you live in the Charleston County section of North Chuck, it's real easy. Sheriff Cannon is your CLEO. He's got no problems with NFA. Here is what you do. Complete your forms and remember to sign them. Put them in a manila envelope along with a copy of your SCDL and write your SSN on the same sheet. On the front of the envelope write "ATF forms for Sheriff Cannon" and put your return contact information including phone number. Take it down to Headquarters drive and give it to the deputy at the front window. Tell him its paperwork for the Sheriff to sign. He may give you a confused look. Tell him that it should go to the Sheriff's secretary. She knows what to do with it. In about 3 or 4 days she will call you and tell you it's ready to pick up. She is very nice and helpful. The Sheriff's appointee will have signed it and it's ready to be mailed off.
Frost if you're still considering this check out the AAC Evolution 9 or the SWR Trident both are very popular. I have a buddy with a couple of Evo's - one in 9 and the other in 40 cal. Might be able to get all of us together one day so you can hear the 9mm can.
Keep in mind you'll need finger prints also, the Chas County Detention Center (jail) has a cool digital machine and they do prints from 6AM til 6PM if IIRC.