Work Flow to start

I need to setup a work flow for their sales dept for a manufacturing company
after getting feedback from them
I have this point in my mind
two cases here
# one for existing profile . (Design )
# One for new profile (design )

For existing profile
# Customers inquire :- This enquiry can be converted to sales order
# Sales dept response by sending the fax (PO)
# Customer response by resending the fax
# based on the above result , it is send to the production dept
# materials produced and dispatched after getting the payment