I have some ringtones from the web as M4R files that I want to modify but they wont drag into the project window

I down loaded a ringtone from Zedge.net

it is a M4R file that came in as a 165,269 bytes and the help instructions for creating a ringtone in GarageBand say

1. Choose File > New.The Project Chooser appears, with categories on the left, and templates for the selected category on the right.
2. In the Project Chooser, click iPhone Ringtone.Ringtone templates appear to the right.
3. Double-click the ringtone template you want to use.
4. In the New Project From Template dialog, type a name for the project.If you want to, you can set the tempo, key, and time signature for the project in the dialog, or change these later while you are working on the project.
5. Click Create.The project opens, showing the timeline.
6. Do any of the following:
   • Drag an audio file from the Finder to add it to the project.
   • This is where it fails as the M4R file will not be dragged into the project
   • I last modified ringtones for my iphone 4s when it came out and the whole process in the GarageBand of that vintage worked just fine I even made a ringtone from scratch but the "Send ringtone to itunes from share" does not work with garageband 11 ver 6.0.5 with Highsierra and its iTunes 12.7.1.14
   • this all was so simple when I last did it a few years ago but now the instructions from apple help that I have copied here for this task do not seem to work
   • Drag Apple Loops from the loop browser, then position them to create the project.
   • Record your own original music or other sounds in the project, using Real Instrument, Software Instrument, and Electric Guitar tracks.
7. When the project is ready, click the Cycle button in the control bar.
8. Drag the ends of the yellow cycle region to cover the part of the project you want to use for the ringtone. Ringtones can be up to 40 seconds long.
9. Choose Share > Send Ringtone to iTunes.iTunes opens, showing the new ringtone in the Ringtones list.