CreateQuoteLine() takes the ID of the quote alternative, it’s automatically linked up to an alternative, a version, a quote, and a sale.
You can choose to add a product by its ERP info or as an NSProduct. In either case, you should set the quantity and any discounts for the selected product.
Create from product key
Create from NSProduct
Reference
Frequently used QuoteLine fields
The line will also include information duplicated from the product (rather than referenced).
For a complete list of fields, see the database reference.