They sit you in an old building and ask you about yourself and your medical history. Then they document all this info before they have you sign a documents and waivers.
Just go to your local recruiter and take the ASVAB. After completing OSUT, you'll become an infantryman (11B). You'll be assigned your unit upon graduating. Make sure to stay in good physical shape.
You express interest and they call you. You will have to answer some basic questions about yourself and take a placement test. Then you will be sent to a medical processing facility to do a medical exam.
