Loading Hierarchies using flat file

Hi experts,

I have requirement to load hierarchies using flat file.

I have to create hier on Person Responsible, sub nodes are Sales Office, Project Definition, Project Type and Project Definition Description. I have file, i need to load into BW.

I dont know much about hier loading, can you tell me what are the Attributes to be inserted and how to prepare the hier loading file which contains HIENM, VERSION, HCLASS, DATEFROM and DATETO.

I dont know these fields are enough to load my hier.

I have created one hier, when i try to activate it's giving error like ' no data exists'.

Can anyone tell me how to prepare file to load into hierarchy?

Thanks in advance,

Venky