To join the Air Force go to a recruiter. He or she will talk to you and make sure you are eligible and then schedule you to take an aptitude test called the Armed Services Vocational Aptitude Battery or ASVAB. This test will help define your strengths and weaknesses and be used to determine your job placing. You can score low enough to be rejected so try hard and maybe even study. After you "pass" you are on your way. The time from be accepted to actually being sworn in varies for each person.