Yes, everyone in the Military is required to go to Basic Training.
It should be as hard or harder than your limits. It is designed to find your limits and try to push you to the edge of what you can endure (or cause you to quit). It is mentally and physically...
Depends on what branch of military your joining, your military occupational specialty, and your resident geographic location.
Basic training gets you ready for the military lifestyle as well as get you in shape and teach you self discipline.
National Personnel Records Centre in St. Louis. See related link.