In the User Edit window, click the Alert Subs tab.
User Alert Subscriptions: Highlight the alert categories to subscribe the user to. Click and drag, or press Ctrl while clicking to select multiple categories.
Clinics Subscribed: If using Clinics, highlight the clinics the user will see alerts for. Take into consideration any clinic restrictions (set in the Clinics tab). Users can only see clinic alerts when they have access to the clinic.