Custom widget

3. In the extend-widgets-bundle folder I created another extra-widgets folder
4. In the extra-widgets folder I created another hello-world-widget folder
5. In the hello-world-widget Folder I created a file hello-world-widget.php in which I placed the following code

/*
Widget Name: Hello world widget
Description: An example widget which displays 'Hello world!'.
Author: Me
Author URI: http://example.com
Widget URI: http://example.com/hello-world-widget-docs,
Video URI: http://example.com/hello-world-widget-video
*/

class Hello_World_Widget extends SiteOrigin_Widget {

    function get_template_name($instance) {
        return '';
    }

    function get_style_name($instance) {
        return '';
    }
}

siteorigin_widget_register('hello-world-widget', __FILE__, 'Hello_World_Widget');

function __construct() {
    //Here you can do any preparation required before calling the parent constructor, such as including additional files or initializing variables.

    //Call the parent constructor with the required arguments.
    parent::__construct(
    // The unique id for your widget.
        'hello-world-widget',

        // The name of the widget for display purposes.
        __('Hello World Widget', 'hello-world-widget-text-domain'),

        // The $widget_options array, which is passed through to WP_Widget.
        // It has a couple of extras like the optional help URL, which should link to your sites help or support page.
        array(
            'description' => __('A hello world widget.', 'hello-world-widget-text-domain'),
            'help'        => 'http://example.com/hello-world-widget-docs',
        ),

        //The $control_options array, which is passed through to WP_Widget
        array(
        ),

        //The $form_options array, which describes the form fields used to configure SiteOrigin widgets. We'll explain these in more detail later.
        array(
            'text' => array(
                'type' => 'text',
                'label' => __('Hello world! goes here.', 'siteorigin-widgets'),
                'default' => 'Hello world!'
            ),
        ),

        //The $base_folder path string.
        plugin_dir_path(__FILE__)
    );
}

function get_template_name($instance) {
    return 'hello-world-template';
}

function get_template_dir($instance) {
    return 'hw-templates';
}

6. In the hello-world-widget folder I created another folder hw-templates in which I added the file hello-world-template.php in which I placed the following code

 echo wp_kses_post($instance['text']) 

After doing all the steps, the widget I created does not appear anywhere. What do I need to do so that this widget appears in the builder and I can use it?