[Question ] how to add fields on trait dynamically

I am building the trait when the application starts. so getting the below fields at side bar as settings

Now I want more field to be loaded (in the below picture 'product' and 'Product Image' ) along with previously loaded field ('Logo Url', 'Redirect Url'). And these two fields('product' and 'Product Image' ) will be coming through an API . I want these two fields ( 'product' and 'Product Image') to be loaded while clicking on that particular section.

So in trait_manager exactly where I have to make the changes (api call for adding fields ) to achieve this. Addition of product' and 'Product Image' these two fields should happen while clicking on the section only ;