How do I install plugin with Mac Firefox?

it’s no different in mac… unzip the file, copy autometa.php to the wp-content/plugins directory, login to the control panel and enable the plugin.

Thanks,I have searched for the wp-content/plugins directory using the Mac search feature and I can’t find it. Is it on my harddrive or on the wordpress site (I have searched there also).

It’s on the wordpress site. Go to where you uploaded the WP files the first time and you should see the following directories as well as some other files.

wp-admin
wp-content
wp-includes

Browse wp-content directory and you should find the plugins directory

See: https://codex.www.ads-software.com/Managing_Plugins#Installing_Plugins

In your case, I recommend Cyberduck as a good FTP client.