To make the changes that you are seeking you need to be modifying files through your server account….. not from the Joomla admin template.
You need to go into your cpanel account and the file manager… navigate to the directory I have listed above and make the changes. It’s not a Joomla administrator function but something your need to be doing at a core level.
And do some reading on the T3V3 template and Joomla 3.0 as the methodology of creating pages and making changes is somewhat different to J2.5.
🙂 There are the functions you can perform from within your Joomla admin account on the template and then there are the modifications that you need to go into core files to change. I, personally, keep a separate record of these changes so – when I update a system – I have a record of the files, or code, that I have changed -> and can update them as required.
Get out there and have fun!