Walk in to the recruiter, they interview you, and if you meet general requirements you get sent to a medical screening and then you pick an occupation field you are qualified for. The USMC will then pick a specialty in that occupation for you to do, and then you get a ship date to boot camp.

Talk to a recruiter make sure you or mentaly, physically meet all requirements to join, you can find a local recruiter anywhere through there website. you can choose how long your contract is or try to opt for the job u want.