Installing Ckeditor

In CI, you never address php files directly. All url's must point to a controller and a method inside that controller (unless you need the index method).
The textarea that you want to combine with CKEditor must be in a view.
You load the view in a controller.

Example:
View is (...)\application\views\test_ckeditor.php

Controller is (...)\application\controllers\Editor.php
(Keep in mind that a controller must have a name that starts with a capital letter).

PHP Code:

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
class Editor extends CI_Controller
{
  function test()
  {
     $this->load->view('test_ckeditor');
  }
} 


Now, the url is https://spokaneesl.com/editor/test
This will show you the page with the CKEditor textarea. The "editor" segment in the url is the controller; the "test" segment is the method (= function) inside the controller.