Hi Alex,
Fortunately we do not have to create every hierarchy from scratch. In many cases the hierarchies are available in an SAP Source System and we can upload them to BW using Business Content DataSources. E.g. Material, Customer, Profit Center, Cost Center, Cost Element, G/L Account, etc.
As a first step investigate thoroughly together with your Source System colleagues which hierarchies are available in the SAP Source Systems.
Best regards,
Sander