Correctly installed MemberWing membership site plugin but won’t register

I correctly installed the MemberWing plugin files in the plugins directory of my new WordPress installation in their own folder but they do not work. Checked that the memberwing.php top file is there in the folder. All as per instructions but does not register with WordPress when I check for new plugins.
I really need my site to be a membership site before I can upload any new content which is a shame since the WordPress plugin is not working. Any comments or help would be welcome.