Take in everything they tell you at recruit training. Your A School will try to teach your job in the Navy, but about the most that can be taught is the basics. They will be able to 'guide' you in the right direction as far as your career goes, and sometimes winds up being the primary role model throughout your career. I still remember my chief, who became my best friend, before he retired. If I ever get around to writing my book, you can be rest assured that his name will appear on the front page as being one of the major influences in my life.
Mail arrives via replenishment or inport.
Remember, hazing is an integral part of building a team. Just don't get upset when it happens, because this is going to be your first test. Laugh along with them, and you will be accepted. Get upset, and you're the newest jerk onboard. Wear your uniform with pride.