I create custom model and it has one2many field like sale order line .But I don't know how to create add a section and add a note in this one2many field.How can I add this like sale order line.My custom order line has the same field with sale order line ,so I try to use sale order line in my custom model.But everything is working fine before save.When save, get order_id problem because order_id is required field and connect with sale order.So,how can I solve my problem?Please guide me how to add (add a section and add a note) in my one2many field.