I need help to start using Download Monitor plugin

I tried adding a new download to a page, but I get this error message:
Fatal error: Call to undefined method DLM_File_Manager::get_filesize() in /home/joselui2/public_html/wp-content/plugins/download-monitor/includes/class-dlm-download-version.php on line 79

If you cannot access your site due to that error, you’ll need to use FTP or Cpanel to delete that plugin from your site files on the server.

BTW, if you are actually using WP3.5.2 – that could be why you got an error – you should get WP updated ASAP so you don’t get hacked.

For help using the plugin, go here:

https://www.ads-software.com/plugins/download-monitor/faq/

Ask questions here:

https://www.ads-software.com/support/plugin/download-monitor#postform