you don’t need to copy the functions.php from parent to child theme, you can simply create the functions.php in child theme directory/folder, and enqueue the bootstrap.css via a hook function, like this.
function wp_bootstrap_starter_child_scripts() {
// load parent style
wp_enqueue_style( ‘parent-style’, get_template_directory_uri() . ‘/style.css’ );
wp_enqueue_style( ‘child-style’, get_stylesheet_directory_uri() . ‘/style.css’ );
wp_enqueue_style( ‘boostrap’, get_stylesheet_directory_uri() . ‘/bootstrap.css’ ); //update the relative path of bootstrap.css file.
}
add_action( ‘wp_enqueue_scripts’, ‘wp_bootstrap_starter_child_scripts’ );
