Hi Sandy,
Okay, I think I understand now what you are reffering to. You want to exclude some of the attachments from the results. You can do that by entering the attachment IDs into this field, comma separated: https://i.imgur.com/AehzD0T.png
To find the attachment ID, go to the media library page, and click on the attachment. The ID will be in the browser address bar like so: https://i.imgur.com/kuO5Wq8.png
The group attachments on that topic are PDF files, that was not included in the mime types list under the options. I have added it here for you: https://i.imgur.com/0J2cmUG.png
Please make sure to add that mime type to all search instances, where you want to return the PDF attachments.
