not sure about AD Army re: DD 368 to transfer service- I'm transferring from Army NG, but I started with my CG recruiter. He/she will email you with a Request for Conditional Release that both of you will sign. You'll probably have to route that to you're admin NCO or to your S-1. At which point everyone's gonna freak out and try to get you to stay in. Anyway, your unit or command will have a checklist for you to do as part of your out processing.
Just to share, my CSM met w/ me multiple times to persuade me stay in..ahem..discourage me from transferring. He gave the big picture about the Army as a whole downsizing but trying to maintain soldiers to keep their budget blah blah blah.
I started preparing my DD 368 packet October last year and it was approved this August. Now I'm slotted for DEPOT in October 30th. Good luck!
p.s I redid MEPS, ASVAB, and I'm E-5 entering CG as an E-3