You can send your users an email notification when you go live by enabling the live event email notification. For events that are Free for everyone, all of your users will receive an email notification that the event is going live. If your live event Requires access and is part of a certain plan or one-time purchase, only those with access to that plan or one-time purchase will be notified.
Navigate to Content, then go to Live Events. Click on Appearance and scroll down to the Notification Email section and toggle the box for Send email notification.
After toggling the box, the email template will be displayed. You can customize the Subject line and the body, so you can tailor it to your users. The only part you shouldn't customize is the section in the body of the email that's under the curly brackets {{ }}.
Once you've customized your email to notify people that your event is live, scroll down and Save your changes.
As soon as you click Go Live under the Stream tab, the email will be sent out to all users that have access to the event.
The email users receive will be similar to the example below:
The image displayed will be the one you selected for the Player Image, under the Appearance tab, and the email will also contain a Watch Now button, so users can watch it right away.