将静态页面添加到自定义帖子类型的阅读设置

I'm currently trying to add a static page to my custom post type. The reason for this is:

-I'd like my client to be able to change a feature image to my archive-our_classes.php, as well as use a call to action block that I've created with custom fields.

I've looked at this answer here, and can't seem to get my code to work - please help! (Note: I did not change their notes from Projects to "our_classes")

Add Static Page to Reading Settings for Custom Post Type

add_action( 'admin_init', function () {
    $id = 'our_classes';
    // add_settings_field( $id, $title, $callback, $page, $section = 'default', $args = array() )
    add_settings_field( $id, 'Our Classes Page:', 'settings_field_our_classes', 'reading', 'default', array(
        'label_for' => 'field-' . $id, // A unique ID for the field. enter code hereOptional.
        'class'     => 'row-' . $id,   // A unique class for the TR. Optional.
    ) );
} );

/**
 * Renders the custom "Projects page" field.
 *
 * @param array $args
 */
function settings_field_our_classes( $args ) {
    $id = 'our_classes';
    wp_dropdown_pages( array(
        'name'              => $id,
        'show_option_none'  => '— Select —',
        'option_none_value' => '0',
        'selected'          => get_option( $id ),
    ) );
}

/**
 * Adds page_for_projects to the white-listed options, which are automatically
 * updated by WordPress.
 *
 * @param array $options
 */
add_filter( 'whitelist_options', function ( $options ) {
    $options['reading'][] = 'our_classes';

    return $options;
} );

I'd love assistance on how to get this to work! Thanks in advance!