Setting up a cron job with Webmin

I am trying to setup a Cron job using Webmin to run every 5 min. It needs to target a .php file and run the php script in that file. When I enter the path to the file in the "Command" field, it doesn't work. I am just wondering what I am doing wrong, and where do I put the file path that I need the Cron job to run.

Thanks!