Exchange Add-Ons: Simple Shipping
To enable the Simple Shipping add-on, you'll go to Exchange > Add-ons and click the Disabled button to the right of the add-on.
Once enabled, you have settings you can adjust. To access your Simple Shipping settings, you can either click the gear symbol to the right of the add-on or go to Exchange > Settings and select the Shipping tab at the top of the page.
In the settings, you'll find General and Simple Shipping settings.
Under the General settings, you have the option to make the global settings changeable for each individual product.
Setting this option to Yes will show an Override option when you're creating a product.
Under the Simple Shipping settings, you can set the price for your flat rate shipping and determine which shipping options will be available (flat rate shipping and free shipping).