How do I save a custom ringtone with IOS 11

I found some ringtones there, but not the main one I use for my phone. I also found some other folders of "unknown artist", and will add artists in my iTunes for them.

Boy, I hate this editor, using Chrome for Mac, whenever I start hitting backspace or use my cursor, the cursor goes all over the place, inserting my next letters where it is, making it very hard to use. Sometimes it pops around for no reason whatsoever. So I gave up and am writing this elsewhere and will paste it here.

I ran a utility to look for all.m4r files, but could not find my ringtone. I probably bought it, but don't remember from where. (It is "House of the Rising Sun").

I looked in my media folder (which is huge as I have *lots* of media). I don't see anything there to tell me where my custom ringtone is.