SAP ByD Organizational Structure setup

Hi,

I am new to SAP ByD and have been working as SAP ECC consultant for several years.

I need to setup organizational structure in ByD for a new client.

It would be great if any one can explain me on how to do it and what is the importance/use of various organizational units and also high light the mandatory organizational units.

If we have approvals on sales and procurement side, should I be doing any additional setting in the organizational units setup?

Thanks for your help and time.

Regards