Hi,

To customize UI for properties on your promotion type, you can create a BlockData for those properties like that

public class CustomProperties : BlockData
{
    public Type Property1
    public Type Property2
}

Then you need register an EditorDescriptor for that block to customize UI in the client side.

[EditorDescriptorRegistration(TargetType = typeof(CustomProperties))]
public class CustomPropertiesEditorDescriptor : EditorDescriptor
{
    public CustomPropertiesEditorDescriptor()
    {
        ClientEditingClass = "js/editors/CustomPropertiesEditor";
    }
}

Finally you create a dojo widget to render those properties using radio button as you want.

Hope that helps.

/Tuan

Is there a good example online showing how I can do this?  ("dojo widget"?)

I'd like to do something similar to how a "MonetaryReward" looks on a promotion.  Ideally I would just look in the code to see how that one works - but I can't seem to locate that source code....

Here is an overral example good for you. https://world.episerver.com/blogs/hakon-nordli/dates/2015/10/learn-how-to-develop-your-own-dojo-widget3/