This plugin allows you to custom an awesome notification box.
Clean=Free of useless links + Free of useless code.
This plugin help you to add a Notification box when user scrolling the page, the notification support HTML and WordPress shortcode. So you can put any content in it, like a Youtube video or others.
This was built considering for everyone to be able to use no matter the WordPress experience, so it's very easy:
wp-responsive-scrolling-notificationfolder to your