The Alerts tab is available from the Resources and Websites pages. It is a filtered view of the Alerts page, displaying active alerts only for the current selected entity (i.e. a device group, resource, DataSource, Service, or instance found in the Resources tree; a website found in the Websites tree). You can further filter the display using the filters provided.
The functionality of the Alerts tab is almost identical to that of the Alerts page. For this reason, please see Managing Alerts from the Alerts Page for more information on filtering, sorting, and responding to alerts from this tab.