You will need to contact a National guard recruiter or Reserve recruiter who will give you contact information for the unit you are trying to apply for. Following that, you will need to attend a separate hiring process/selection at the unit you wish to attend.

The Prior service program is one of the Air Force’s most selective programs. We often have prior Army, Navy and Marines that go years without jobs. Even though they have all passing PAST tests. The Air Force’s priority is new enlisted for pipeline slots, then maybe backfill with AFR or ANG students, and then finally Prior Service. So I would really recommend not going in the Army in general, and just go straight in for PJ if that is what you ultimately want to do. The reason I say this is because there really is not a career field you can go into that is going to make you more prepared, PJs need to be good at all of that stuff including the medical and "ground pounder" aspects of the job. Additionally, you can still attend classes or just do online classes while you are in the Air Force. The biggest advantage you will gain from being in the Army is an appreciation for the Air Force to be honest.   

Not true, you will get more civilian rescues in a guard unit but it doesn't mean you don't get to do your job in active duty. Honestly, the Alaska unit gets some of the most action as far as civilian rescues go.