Question in regard to the 747 two or three engine taxi operations

[Arzenim]

Hi there,

I am interested to know whether the APU has to be running and does it have to be on bus when two or three engine taxi operations are commenced.

Also are there any other procedures in that regard other than the fact that you have to acknowledge thermal warm up and cooldown times (5 minutes if I am not mistaken) and monitor the engines a little closely ?

Thank you very much