The Komento Plugin allows you to use the comment component Komento with the jDownloads series 3.2.x. This version of the plugin does not support older Joomla or jDownloads versions.
Make sure that the option "Activate support for all Joomla content plugins?" is activated in the jDownloads configuration Frontend tab!
Please copy the unzipped file to the Komento component subfolder '/komento_plugins' in your Joomla installation. Then check the settings in Komento.
Comments are only possible in the Downloads details page.