Think of it as actually adding your factory options to the vehicle record, not the order. Therefore if you are creating a factory order quotation you'll be 'building' your car before the details are even pulled into an order screen. If you have read the section on creating an order you'll already have covered this.
If you are building your deal in an order screen having already selected your car, and find that you need to change the factory options you'll need to edit the vehicle record. To do this click on edit under the vehicle detail within the grey panel.
This opens the vehicle record in a pop up so you can edit basic vehicle information, colour and trim, as well as factory options,or technical data. Once you have edited simply click save and the changes will be reflected in your order.