Download the PHP SimpleComments zip file and unzip it to a directory on your computer.

Connect to the web server which runs your copy of MovableType, using whatever method you use to upload files. Upload all seven PHP scripts to the PHP plugins directory in your MovableType directory. Let’s pretend that your MovableType directory is ~/mt; then your PHP plugins directory should be located at ~/mt/php/plugins. If the ~/mt/php directory does not have a plugins directory in it yet, then create one. If the ~/mt/php directory does not yet exist, then you probably aren’t using a version of MovableType that supports dynamic publishing in the first place.

N.B.: do not upload the files to ~/mt/plugins. That is the directory for Perl plugins. If you put PHP plugins there, the dynamic publishing engine will carry on blithely unaware of their existence.