Alerts start immediately after the sign up form is submitted. Twitter Mentions (alerts) happen three times per account, while SMS is active until a user requests alerts to stop.
GlobalEntryNow is fetching appointments for your location every 2 to 3 minutes, and will alert you when a new one is found. You should be on the lookout for an appointment that works best for you, and ready to schedule it using the TTP website.
There are two different types of alerts: SMS (text) and Twitter mentions. You will have the option to choose one an alert type during sign up. Take a look at the below demo of each sign-up experience so that you know what to expect: