Your child theme was not correctly including the parent CSS.
I add this to your child theme functions file and the layout is now correct:
add_action( 'wp_enqueue_scripts', 'sf_theme_enqueue_styles' );
function sf_theme_enqueue_styles() {
wp_enqueue_style( 'parent-style', get_template_directory_uri() . '/style.css' );
}
You just need to add widgets to the Sidebar 1 widget area, Appearance => Widgets.