The Snooze option for Informant-hosted events and tasks works when the notification/alarm comes up and you press "View" or on the notification in the Notification Center. The event/task detail comes up and you then see a Snooze button that will snooze for 9 minutes.

This feature only works for events and tasks hosted by Informant. It does not show up for iOS Events and Tasks. iOS Events/Tasks alarms are handled by iOS itself and Pocket Informant does not affect those.