Log into your account and select Notifications from the left-hand navigation bar. Next to the Subscriber header at the top of the screen you'll see Gear icon which, when clicked, will expand a dropdown menu. In the dropdown menu, click on Add Subscriber.
Add an Email subscriber
Add an SMS subscriber
Fill out the required information, click Add Subscriber, and you're done! This user will now be subscribed to all notifications from your Statuspage.
Note that only the subscription types that have been enabled on the notifications settings page will be available in the Add Subscribers 'Type' dropdown. To choose which subscription types you would like to enable, visit the 'Settings' section on the Notifications page, and select which types you would like to allow in 'Notification Delivery Types'.