To push notifications with a custom logic automatically when some event is fired , for example you add new product to your site and want to notify to all subscribers , just go to your account click “my apps”
then select your app and click on “manage app” button then click on “Send Notifications Immediately”,
then “Advanced – push notification by your own logic” then copy the code and paste in your desired place in code for this action you may need a developer , but its so easy so even you can do it.