How is the day in the life of a 13F? Also, is there any exercises that they focus on?

You have to be able to do what the infantry does, only better because you will be held to a higher standard, and you have to be able to do your job. You will be out alone in sector or with one other person, sporadically. The rest of the time, you will be acting as an infantryman with your platoon.

Depends on where you go and rank. South Korea was far different than Ft. Bragg, just focus on becoming proficient on your job!

I’m not mounted I ruck a lot

Please ask your recruiter damn it. Fisters are attached to Infantry unit- so you do everything they do while calling of fires from your Arty unit. Normally you stuck with an Plt Ldr or Co Cdr.