Downloaded the “Piano 4 hands” template from Project Templates – Dorico but have absolutely no idea how to actually use it in a project. Dorico doesn’t seem to know what a .dtn file is, and neither do I. 
Hope you can help
If you download it, it should come down as a .dorico file. Of course, a .dorico file is actually a zipped up bunch of stuff, so it seems like your computer has automatically unzipped the .dorico file. That isn’t normal.
Here is the file I get when I download the template:
Piano 4-hands.dorico (3,2 Mo)
Yeah, it’s downloaded a couple of files and folders. I’ll see about trying to download the single file as is. Much like myself at the end of a long day, my Mac can’t wait to get unzipped!
I get a zip file when downloading. You can replace .zip with .dorico.
Jesper
The file on the webpage is a “straight” .dorico file. It’s not a .zip file.
It’s possible that some browsers might see the .dorico file as a zip, and unzip it. It’s usually safer to uncheck preferences to open or process incoming files, as a defence against malware.
(Though many file formats are zipped containers, like MS Office files, Finale .musx, etc…)
Anyway, Charles has provided the file, above, if you can’t get it from the page. Also, I’ve created a 4-hand Dorico file for Faure’s Dolly suite, here:
Weird. What browser are you using?
Ah, that explains the zip files. No, I don’t have that checked in Safari settings.
Jesper
Yep, I’m getting the same thing
Aha! This solved it - thank you, Jesele! 