Joining oe_order_lines_history and oe_order_lines_all

I am new to Oracle and needing to do a report that will compare original order quantities to the existing shipments essentially to compare availability at shipment. This is what I have put together so far but i still have something missing as I still having some duplications. So the top three I don't need but the bottom 3 I do. Any suggestions to clean up the joins and include all from oe_order_lines_all and just be able to grab the original quantities from oe_order_lines_history?

select ont.oe_order_lines_all.Header_ID, ont.oe_order_lines_all.Line_Number, ont.oe_order_lines_all.Ordered_ITEM, ont.oe_order_lines_all.Ordered_QUantity, ont.oe_order_lines_history.ordered_quantity as Original_Quantity, ont.oe_order_lines_history.shipped_quantity