NCAA Blocked FG

[DJ_NV]

4/10 from the B-30 yard line. Team A lines up to kick a FG. You are under the GP as BJ or FJ. Kick is obviously deflected at or around the LOS but you don't know where or by whom. The low kick continues (only deflected partially) down where it bounces around the B-5 (no players around yet) and bounces into the end zone.
What are the proper mechanics? Whistle? If it's touched by B beyond the line then it's a live ball, otherwise it's dead. How do the guys under the GP know? Do we let it go and then ask the HL/LJ what happened after the play and call it back after the fact?

thanks