Can I use Terms of Service Plug-in for Single site?

I’d like to add the Terms of Service plug-in to my client’s site. When I locate the plug-in it from within the Plug-ins tab it says it requires multi-site. However, when I visit the “learn more” link for the plug-in there are instructions for using it on a single site.

My question is, is it usable on a single site? If only on a multi-site, what will I need to do to get this plug-in to work?