http://www.brentozar.com/blitz/configure-sql-server-alerts/
and this is also quite a useful link that explains what some of the error codes mean by Robyn Page and another SQL guru:
https://www.simple-talk.com/sql/database-administration/sql-server-alerts-soup-to-nuts/
Below is the SQL Script for Setting up alerts with severity 16-25 and SQL Server Alerts 823-825 and 832. I added the 832 alert to the script, but the main body of the script is from Brent Ozar at the first link above. When you run the script you need to do a Find and Replace on 'DBA Team' and substitute it for whichever SQL Server Agent Operator that have configured and want to be notified.
USE [msdb]
GO
EXEC msdb.dbo.sp_add_alert @name=N'Severity 016',
@message_id=0,
@severity=16,
@enabled=1,
@delay_between_responses=60,
@include_event_description_in=1,
@job_id=N'00000000-0000-0000-0000-000000000000';
GO
EXEC msdb.dbo.sp_add_notification @alert_name=N'Severity 016', @operator_name=N'DBA Team',
@notification_method = 7;
GO
EXEC msdb.dbo.sp_add_alert @name=N'Severity 017',
@message_id=0,
@severity=17,
@enabled=1,
@delay_between_responses=60,
@include_event_description_in=1,
@job_id=N'00000000-0000-0000-0000-000000000000';
GO
EXEC msdb.dbo.sp_add_notification @alert_name=N'Severity 017', @operator_name=N'DBA Team',
@notification_method = 7;
GO
EXEC msdb.dbo.sp_add_alert @name=N'Severity 018',
@message_id=0,
@severity=18,
@enabled=1,
@delay_between_responses=60,
@include_event_description_in=1,
@job_id=N'00000000-0000-0000-0000-000000000000';
GO
EXEC msdb.dbo.sp_add_notification @alert_name=N'Severity 018', @operator_name=N'DBA Team',
@notification_method = 7;
GO
EXEC msdb.dbo.sp_add_alert @name=N'Severity 019',
@message_id=0,
@severity=19,
@enabled=1,
@delay_between_responses=60,
@include_event_description_in=1,
@job_id=N'00000000-0000-0000-0000-000000000000';
GO
EXEC msdb.dbo.sp_add_notification @alert_name=N'Severity 019', @operator_name=N'DBA Team',
@notification_method = 7;
GO
EXEC msdb.dbo.sp_add_alert @name=N'Severity 020',
@message_id=0,
@severity=20,
@enabled=1,
@delay_between_responses=60,
@include_event_description_in=1,
@job_id=N'00000000-0000-0000-0000-000000000000';
GO
EXEC msdb.dbo.sp_add_notification @alert_name=N'Severity 020', @operator_name=N'DBA Team',
@notification_method = 7;
GO
EXEC msdb.dbo.sp_add_alert @name=N'Severity 021',
@message_id=0,
@severity=21,
@enabled=1,
@delay_between_responses=60,
@include_event_description_in=1,
@job_id=N'00000000-0000-0000-0000-000000000000';
GO
EXEC msdb.dbo.sp_add_notification @alert_name=N'Severity 021', @operator_name=N'DBA Team',
@notification_method = 7;
GO
EXEC msdb.dbo.sp_add_alert @name=N'Severity 022',
@message_id=0,
@severity=22,
@enabled=1,
@delay_between_responses=60,
@include_event_description_in=1,
@job_id=N'00000000-0000-0000-0000-000000000000';
GO
EXEC msdb.dbo.sp_add_notification @alert_name=N'Severity 022', @operator_name=N'DBA Team',
@notification_method = 7;
GO
EXEC msdb.dbo.sp_add_alert @name=N'Severity 023',
@message_id=0,
@severity=23,
@enabled=1,
@delay_between_responses=60,
@include_event_description_in=1,
@job_id=N'00000000-0000-0000-0000-000000000000';
GO
EXEC msdb.dbo.sp_add_notification @alert_name=N'Severity 023', @operator_name=N'DBA Team',
@notification_method = 7;
GO
EXEC msdb.dbo.sp_add_alert @name=N'Severity 024',
@message_id=0,
@severity=24,
@enabled=1,
@delay_between_responses=60,
@include_event_description_in=1,
@job_id=N'00000000-0000-0000-0000-000000000000';
GO
EXEC msdb.dbo.sp_add_notification @alert_name=N'Severity 024', @operator_name=N'DBA Team',
@notification_method = 7;
GO
EXEC msdb.dbo.sp_add_alert @name=N'Severity 025',
@message_id=0,
@severity=25,
@enabled=1,
@delay_between_responses=60,
@include_event_description_in=1,
@job_id=N'00000000-0000-0000-0000-000000000000';
GO
EXEC msdb.dbo.sp_add_notification @alert_name=N'Severity 025', @operator_name=N'DBA Team',
@notification_method = 7;
GO
EXEC msdb.dbo.sp_add_alert @name=N'Error Number 823',
@message_id=823,
@severity=0,
@enabled=1,
@delay_between_responses=60,
@include_event_description_in=1,
@job_id=N'00000000-0000-0000-0000-000000000000'
GO
EXEC msdb.dbo.sp_add_notification @alert_name=N'Error Number 823', @operator_name=N'DBA Team',
@notification_method = 7;
GO
EXEC msdb.dbo.sp_add_alert @name=N'Error Number 824',
@message_id=824,
@severity=0,
@enabled=1,
@delay_between_responses=60,
@include_event_description_in=1,
@job_id=N'00000000-0000-0000-0000-000000000000'
GO
EXEC msdb.dbo.sp_add_notification @alert_name=N'Error Number 824', @operator_name=N'DBA Team',
@notification_method = 7;
GO
EXEC msdb.dbo.sp_add_alert @name=N'Error Number 825',
@message_id=825,
@severity=0,
@enabled=1,
@delay_between_responses=60,
@include_event_description_in=1,
@job_id=N'00000000-0000-0000-0000-000000000000'
GO
EXEC msdb.dbo.sp_add_notification @alert_name=N'Error Number 825', @operator_name=N'DBA Team',
@notification_method = 7;
GO
EXEC msdb.dbo.sp_add_alert @name=N'Error Number 832',
@message_id=832,
@severity=0,
@enabled=1,
@delay_between_responses=60,
@include_event_description_in=1,
@job_id=N'00000000-0000-0000-0000-000000000000'
GO
EXEC msdb.dbo.sp_add_notification @alert_name=N'Error Number 832', @operator_name=N'DBA Team',
@notification_method = 7;
GO
