No interview process for joining the military. You need to take the ASVAB and the better the overall score the more job options that are available. If you don't your ability in basic math, sci., technology, or mechanical knowledge there is free material to study or paid for study books that will help you get ready to get into the military with the score you need for a job field you prefer.
If the job is open then you have a good chance getting the job and any bonuses that may be offered.