move fields in sitlverstripe

Page.php

<?php

class Page {
    function getCMSFields() 
    {
        $fields = parent::getCMSFields();
        $publishingDetails = ToggleCompositeField::create(
            'PublishingHolderToggle',
            'Publishing',
            $fields->fieldByName('Root.PublishingSchedule')
        )->setHeadingLevel(4);
        $fields->removeFieldFromTab('Root', 'PublishingSchedule');
    }
}