Filtering messages by message header content

I've found by using filters in Outlook that I can effectively screen out most spam messages based on a few terms found (or not found) in the email header. See "RFC 7208 Sender Policy Framework (SPF)".

If any of: SPF:fail, SPF:Softfail, or SPF:permerror are found in the message header, the message is likely spam.

It works well enough that I'd like to try implementing it on the email server. However, When I try to set a filter for the header, all I get are dialog boxes for "Name" and "Matches" without any explanations what is being asked, or how it is processed.