I know for a fact where sunflower2 is stuck because I'm the one trying to help her! Here's what we've done and where we are stuck:
6. Open the Calibre_Plugins folder DONE
7. Select one of the zip files in that folder DONE
8. Click on Add SHE DOESN'T SEE AN "ADD" BUTTON
I know I had problems several months ago and I was finally able to figure it out, but I can't seem to remember how I did it. Maybe we unzipped incorrectly? Just can't figure out why we don't have an "Add" button.