[SOLVED] Power Up A Stack

I've just received 5 pc6248s and I want to build them into a stack.

1. The switches are all used so do I have to factory reset them before building them into a stack?

2. From what I read in the Dell Technical White Paper I have to power up the switches sequentially (the manager, the stand-by,...). Do I have always to power up the stack that way or is it just applied one time when building the stack?

Thanks all.