How to edit a site with CodeIgniter

I'm trying to edit a site built with Codeigniter. I just want to add an extra page to the side menu but it's tied down by user permissions and stuff like that and I can't figure it out.
I just installed the framework and it's running on Xampp, but I don't know how to edit the site using it as this is my first time and I'm new to Web development in general. I'd really appreciate your help as I'm working against time. 
azarchatrandom
Thanks.