Export a Sales Quotation that is already created and see how it exports to learn the field names and which ones are required and optional. You also need a 'name' for every line in the quote - do you have that information also?
(From the help on the Import page):
If you want to import sales order having several order lines; for each order line, you need to reserve a specific row in the CSV file. The first order line will be imported on the same row as the information relative to order. Any additional lines will need an addtional row that does not have any information in the fields relative to the order.
As an example, here is sample CSV file of some quotations you can import, based on demo data.
"Order Reference","Supplier","Destination","Pricelist","Order Lines / Product","Order Lines / Quantity"
"PO000020","ASUSTeK","Stock","Default Purchase Pricelist","ADPT",20
,,,,"CARD",30
,,,,"C-Case",40
"PO000021","Axelor","Stock","Default Purchase Pricelist","CD",5
,,,,"CPUa8",15