WordPress.org

The installation process is not as easy as with most other plugins, but i think it shouldn't be too hard using this list:

1. Download the complete package
2. Extract the package using any programm you want (i.e.: 7zip)
3. Upload the extracted folder, including all subfolders (no matter if empty or not) to the plugin directory of your wordpress installation (/wp-content/plugins/)
4. Activate the plugin in your wordpress administration center
5. If necessary (script will tell you) , create the folder "img" as subdirectory of the wpmathpublisher directory and set it to chmod 777
6. Done. Go for it!