Moved controller 'page.php' out of 'controllers/admin' directory and checked if the functions are still working.
Deleted controller 'welcome.php' and view 'welcome_message.php'. Created two view files '_layout_main.php' and '_layout_modal.php' as the main layout of the admin panel. Created a controller 'dashboarh.php' to 'controllers/admin' directory as the home page of the admin panel.
Created new folder 'public_html' in the project root directory and it will be the placeholder of the bootstrap files. Download twitter bootstrap, unzip, and moved all the files to 'public_html' directory.
Modified 'config/autoload.php' to load url helper. Modified '_layout_main.php'. Added html codes, added reference codes to css and js files. Modified controller 'dashboard.php' to load the main layout and modal layout  files. Added meta title to the Admin_Controller.php that will be the title for all the pages in the admin panel.
Created directory in 'views/components' and it contains the html templates for the header and footer. Created new files 'components/page_head.php' and 'components/page_tail.php' that serves as the header and footer template of admin panel.
Created directory in 'views/admin' and moved the files '_layout_main.php', '_layout_modal.php' and the directory 'components' to it to organize the files between the admin and public side.
Replace the bootstrap file with the version used by the tutorial because the latest version is not compatible with the tutorial.
Modified controller 'dashboard.php' to properly locate the '_layout_main.php' and '_layout_modal.php' views. Modified the '_layout_main.php' by adding navigation and container divs to divide the dashboard. Modified the 'components/page_head.php' and 'components/page_tail.php' to reduce redunduncy of code. Modified '_layout_modal.php' view by giving it a style.