I installed and activated the plugin on a hosted WP install. I clicked on Mailing Lists in the Admin dashboard. Other than an ad asking to rate the plugin, there is nothing else. Just white space. I click on integration which shows info on an API key but no documentation or explanation as to what this is for or why it is needed. As there is no documentation for this plugin, and the author says simply "install it and use its, its pretty easy", I have to assume its broken and/or doesn't work.