Code:
/usr/bin/php -q /home/igor/public_html/pages/cron.php >>/home/igor/public_html/pages/cron_log.txt 2>&1
1. Replace 'igor' with your cPanel username
2. This logs any errors or output to cron_log.txt which helps with debugging, etc. By adding an echo command outputting the time/date will keep a record of the file running.
3. Depends on where you got the cron file, if you did not write it yourself. Some scripts require a special variable to be added to the URL when run from the web and these cron jobs need to be run using wget.