Let's assume that your sourcetype is WinEventLog:Security and your lookup file is called EventCode.csv .
On your Search Head, navigate to the app that should own the lookup file and then do:
Settings -> Lookups -> Lookup table files -> New -> Choose File -> Save
Then do:
Settings -> Lookups -> Lookup definitions -> New -> Name(="EventCode") -> Lookup file(="EventCode.csv") -> Save
Then do:
Settings -> Lookups -> Automatic lookups -> New -> Name(=EventCodeAutoLookup) -> Apply to sourcetype named(="WinEventLog:Security") -> Lookup input fields(="EventCode") -> Lookup output fields(="message summary")' -> Save
Then do a debug/refresh` on the search head.
No all events with a field EventCode and sourcetype of WinEventLog:Security will automatically call lookup to get message summary field values. You can skip the last step and do it manually within the search by adding | lookup EventCode EventCode OUTPUT "message summary" .
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