You take the ASVAB, which gauges your cognitive skills and suggests jobs based on test scores. You can take it again if you score low and desire a certain job (I believe that there is a waiting period). The basic 'interview process' is do you want such-and-such job. You work towards that, you get it. Never go in under the lie of 'just do this job you don't want and then change later'. That's nearly impossible to do.