To search for file names, leave the Query field blank, and put your search in the "Include Files" field. So if you want to search for all PDF files, use *.pdf in the Include Files field. If you want to search for all files with golf in the name, use *golf*

To search inside all PDF files, use *.pdf in the Include Files field, and put your text to search for in the Query field. Note that you'll need a PDF file handler to be able to search inside PDFs.

To search for folders, you can enable the "Show folder names that match the "include files" filter" option on the Advanced tab.

Hope that helps!