Basic query on connecting a pair of Phantom - how?

[MountainGuy]

Thanks. Is Dialogue needed to run stereo or can one simply attach the optical to one Phantom and then that broadcast to the other Phantom?

And with Dialog:
a. It is just USB plug and play so that all computer sounds now go through the dialogue and phantom?
b. Is there cable between Dialog and Phantoms or is it wirelessly connected?

Again apologies for these basic questions. I'm sure it is super simple for you owners.

Thanks!
MtnGuy