What roles are really in control in pick (arsaw)

I know how they go on the comand but some confuse me OM-the chief AM-area babysitter PA-the ones doing of production managing PG- what hell is that Im asking because some girl said to be the PG was going to write up for TOT 20 mins when we had just returned from break and we always get a new station after it not even took me 1 minute from the clock in station to my actual station wich was a few steps from it