Trying to download "Zoom" software but get error message "could not be saved because the disc/folder/file is write-protected"

I am trying to download the software to allow me to join a meeting that will be held via Zoom. Found advice here https://linuxhint.com/install_zoom_ubuntu/ So I went to the Zoom web page chose the appropriate package but when I hit the download button I got the error message "could not be saved because the disc/folder/file is write-protected" even before I had been asked the directory in which I wished to save the file.

Is my whole disk write-protected? How do I install software if this is the case?