Hi,
yes, in order to have a customize how the widget is displayed in the frontend in the sidebar you would need to copy function widget() from wpadverts/includes/class-widget-ads.php to your own widget() function and the customize.
Once you do that make sure that in wp-admin / Appearance / Widgets panel you have your custom widget added to the sidebar and not the default WPAdverts Recent Ads widget.
I’ve copied the content of the original function to the new one, but nothing happens. I even added the widget once more to the sidebar in the admin panel.
No matter what I try, I see only the original widget ads.
Now it seems to work. I had to remove the third parameter from the function:
add_action( ‘widgets_init’, ‘my_widgets_init’, 100 );
add_action( ‘widgets_init’, ‘my_widgets_init’); without 100 works.