Still stuck, but just adding another update.
I found a
reference on another board where someone else was having the same problem. She apparently figured it out, but never posted the fix. :/
In reply to that thread it was suggested that she type cd desktop in Terminal. I tried that and got dd: /dev/disk1: Resource busy
The micro SD card is new. Before the last try, I reformatted it because I was afraid that my previous attempts may have left files on their that would mess up the process.
Same questions: what am I overlooking? what am I doing wrong?