Placed a few miles away from where the recruitment is. This is where the hard core fighters then go after training in the recruitment offices.
aka - where the youngins go once they've earned their keep, and can prove themselves worth.
It's just like a normal army base. There are officers and places where only certain officers can go, and places for the soldiers can go. Like a mess hall, gym, and others.
Training can be rough, but most say it's worth it. After ten years the new recruits can opt to leave or stay. After that they have that option almost at the end of each year.
But beware - deserties are not treated kindly.