Copy the pgp file to your text editor and save it as vendorname.asc
Note the extension type. In Kleopatra go to import and chose "file" and scroll to where you saved the .asc file.
I'm not too familiar with TOR security/privacy, but is there any extension or addon/plugin that allows you to select text and download directly as an asc file? Or is it best to just copy/paste into notepad? Sorry if this is already mentioned in a major thread/tutorial, still a bit of an OpSec noob!
Note the extension type. In Kleopatra go to import and chose "file" and scroll to where you saved the .asc file.