Keep in mind that header filtering at the download level throws away data permanently. You'd have to re-download headers again over the impacted range to get the data back.
That said I use header filtering.
1 - Generate a new filter profile with things you want to reject or accept. Mine contains:
"PRiVATE.*\[newzNZB\]"
"[.]exe[.]rar"
"[a-z0-9]{24}.*[a-z0-9]{24}"
As "Subject Reject" You can filter specific posters out too.
"[a-z0-9]{24}" Is a "poster reject" I have this in my header filter.
2 - In the options select "Open Data Folder" then exit Newsbin.
3 - The default configuration file is named "Newsbin.nbi". You can edit it with wordpad or another text editor. I use "visual studio code" which is a free full featured editor from MS
[ALT.BINARIES.BLA]
Active=1
DisplayAge=0
DownloadFilter=HeaderFilter
Parent=Stuff
Each group has an entry like this one. Adding you new filter like the bolded line with the name of the new filter you generated will apply it to the group.
[STUFF]
DownloadFilter=HeaderFilter
Assuming you've moved your groups into different topics, you can add the filter to the parent of the groups and it'll apply to all groups in the topic.
Testing 1 - While working with this, you might want to add this to settings
[Settings]
SaveGZ = 1
Instead of deleting the header downloads, it'll save them in the "Processed" folder in the data folder. New header downloads go into "Import" and finished header downloads go into "Processed" so while testing this, you can save the header downloads, play with the filters. Moving the files from "Processed" back to the "Import" will re-feed the headers.
2 - If you have a specific large group you don't want to mess up. You can go into the "spool_v6" folder in the data folder and make a copy of any group or copy them to a different folder. Then you can wipe and feed headers over and over to a specific group while testing the filters and simply copy the saved group back when you're done
3 - Make a backup of the NBI before you edit it so you can always copy the backup over the one you've changed.