SD - need answers !

hi friends ,am unable find the answers for the following questions

pls help me ...

Can the document be entered only with reference to a preceding document?

Should the existing customer-material info record be taken into consideration?

Should the delivery date be proposed?

Must a customer number be entered when creating a document? For example,

assortment modules can be entered without reference to a particular customer.

How should the system respond if the division entered in the header deviates from the division in the items?

Should a credit limit check be made?

Can an incomplete document be saved or must all data be complete?

Which partner functions are allowed and which ones are mandatory?

Thanks,

ganesh