Multi-Site logic

Folks,

We're using Vantage 8.808.809 and are planning how to use the Multi-
Site but I can't find anything on how information flows from SO to PO
and from Company A to Company B and or C.

Setting up Suppliers and Customer who can be Global / Inter-Company /
IC / Partners and the External Company Maintenance.

Does anybody have the steps to get an order to ship while sourcing
material through Multi-Site?

Kind Regards

Ilsa