There are a couple of ways to do a build. You can build it yourself if you have the skills using a Form 1. First, you fill it out and send it with the 200 tax stamp. Then you wait and wait and wait and when you get it back approved, you build what you want.Then you engrave it and its all good.
The other way is to contact an 07/02 FFL and have them build it. You just give them the gun, tell them what you want and they do it all. Then, you fill out the Form 4, pay the Tax, and wait and wait and wait and when it comes back approved, they give you your gun back with the Form 4.
If you want it SBR'ed and integrally suppressed, it'll be a two stamp gun...one for the SBR and one for the suppressor, for a total of 400 bucks for the two stamps, plus whatever you spend having it done.