What is the difference between automated Notifications and Instant Alerts

Automated Notifications are based on rules that you define. They do contain a certain criteria when to fire and may contain some weekdays / time intervals when the rule shall be enabled. If the rule is enabled and firing criteria is fulfilled, the Notification will fire automatically without any user intervention.
Instant Alerts are different. They explicitly get invoked by the user via a click on the particular Instant Alert icon in the main screen.