To install debugbar in codeiniter project follow the below steps

1. Enable Hook.
..* Open /config/config.php
..* Search $config['enable_hooks'] and replace with $config['enable_hooks'] = true;
2. Copy debugger_view.php file into /application/view folder.
3. Copy hook.debugger.php file into /application/hook folder.
4. Copy hooks.php file into /application/config folder.
..* if you already using hook in your application just copy two array variable from hooks.php to /application/config/hook.php