Hello BradW,
We would be happy to assist you in any way we can. To edit PHP files already uploaded to the server you can use either the Edit or Code Edit options in the cPanel File Manager.
To edit PHP files on your local computer I would recommend a plain text editor such as Sublime Text, Notepad or TextEdit (depending on your operating system).
Please let us know if you have any additional questions or need further assistance.
Regards,
Christi N.