Solved. Instead of clicking on the link to download the zip file I right clicked and chose "Download Linked File as..” I was able to drag the file into KM.
I see the plug in now and didn't need to restart or anything. Thanks for bearing with me on this.
I seem to be unable to install my first plug in. I download a plug in from https://www.keyboardmaestro.com/main/third-party-actions.
Yes, I right clicked on the link and downloaded the zip into my downloads directory so that Finder did not automatically unzip. I drag the Zip file over on top of the KM icon in the dock but nothing happens in KM. The plug in groups folder is not created. If I try it again, KM complains that the imported action already exists.
There is no such thing as a plug in groups folder.
Once you’ve installed a plug-in it is available to use as a regular KM action so if you display the list of available actions you will see a category called Third Party Plug Ins. Have a look at post #4 above where you’ll see a screenshot that should help you…
Then it has imported it. Choose the Keyboard Maestro Menu Item Actions → Show Actions. And have a look in the smart folder called Third Party Plug Ins: