How to add a filter that filters a custom property (device_location) to this alert widget

SELECT COUNT([AH].AlertHistoryID) AS [Alerts]

, SUBSTRING(TOSTRING(DATETRUNC('day', [AH].Timestamp)), 1, 6) AS [date]

FROM Orion.AlertHistory AS [AH]

WHERE DAYDIFF([AH].Timestamp, GETDATE()) < 30 GROUP BY DATETRUNC('day', [AH].Timestamp)

ORDER BY DATETRUNC('day', [AH].Timestamp)