Wtr p.o.a or other work?

Not trying to hijack this thread (sorry I guess that’s what I’m doing though) but I will be in this position on Monday.

I will be the passenger watching and learning from the driver as he does his day to day duties and I will be paid per tacho hours worked directly from the machine in the cab apparently.

So my card will be in slot 2 and be recorded as I’m on POA for the whole time?

Can I change it to other work for example?

Can i add manual entries when I put my card in etc?

As I have ever used slot 2 and dont want to not be paid