Opening a Nucleus course notebook from download

For each course there is a link for a course notebook I can download to my Mac. I’d like to keep a copy locally.
I download the file.
I select the path where the downloaded file resides from the finder window using Ctrl+click and copy the pathname.
If I select Open from Path I get a message saying it cannot find the path. I enter the path only.
If I try Open from URL, the error is that the file is not a JSON. I enter the [path]/filename.ipynb

I ended up uploading the downloaded file (w/upload icon)into my workspace and everything works fine.
Just trying to understand, why neither of the Open functions work. Any ideas what I’m doing wrong?

On a Mac you have to open terminal, move the notebook to the desired directory, navigate there, then start Jupyter. The Open Path - which I still could not get to work from Ananconda/Jupyter apparently works relative to the directory in which you opened Jupyter, does not allow opening files outside of that base directory.