If you bothered to take heed of the letter that your unceremonious arrival most of the basics are covered there. Your time shenanigans are apparently not unique to our universe, and in this world they've decided to start pulling people in.

There's seemingly no way back except by the whims of said time bullshit, so in the meantime you're welcomed by the facility to take part in military school. I do hope you can march better than you can not be a pretentious dick.