In the Email Management Tools section, you should find a link labeled "Aliases / Forwarding". Click that link. Click the Add Forwarder link that should show on the following screen. You'll be given the option to enter an email address, to the right of which is an arrow and a text box that indicates where email sent to that address should ultimately go. The "pipe" comes in with that text box: you will want to literally type the "|" (commonly referred to as "pipe"), followed by the full path to SupportTrio's pipe.php file. For example, if your account was located as "/home/account", and your SupportTrio was installed as "/home/account/public_html/trio", then what you would type here is "|/home/account/public_html/trio/admin/cron/pipe.php". That tells your mail server to pass the entire content of email sent to this address to the pipe.php file, which will then log it in your database.
You will also need to create an account using the same email address in SupportTrio, which lets it know what to do with the email once it is read. To do that, click on the Settings menu, drag your mouse over the Email Parser item, and then click the Email Account Settings menu item. From there you can create the new account -- make sure the Email Setting Type you choose is "Pipe" instead of the default "POP". Enter the email address you entered in CPanel and choose which department to which you will assign the tickets (and any other options you like). Finally, click the Add Email Account button, and you're done.
Please be sure to set the CHMOD for /admin/cron/pipe.php file to 755 so the server can execute it!