Bootstrap is a popular front-end framework that provides a set of CSS and JavaScript tools for building responsive, mobile-first web applications. You can use Bootstrap with a CakePHP application to create a modern and professional-looking user interface.

To use Bootstrap with a CakePHP application, you will need to follow these steps:

1. Install the Bootstrap CSS and JavaScript files: You can download the latest version of Bootstrap from the official website (https://getbootstrap.com/). Extract the downloaded zip file and copy the css/bootstrap.css and js/bootstrap.js files to your application’s webroot/css and webroot/js directories, respectively.

2. Include the Bootstrap CSS and JavaScript files in your application’s layout template: You can use the HtmlHelper to include the Bootstrap CSS and JavaScript files in your application’s layout template. For example:

echo $this->Html->css('bootstrap.css');
echo $this->Html->script('bootstrap.js');

3. Use Bootstrap’s CSS classes and JavaScript functions: You can use Bootstrap’s CSS classes and JavaScript functions in your application’s views to create a professional-looking and responsive user interface. For example, you can use the btn class to create a button:

echo $this->Form->button('Click me', ['class' => 'btn btn-primary']);

By following these steps, you should be able to use Bootstrap with your CakePHP application to create a modern and professional-looking user interface.

Note: These are just the basic steps for using Bootstrap with CakePHP. There are many additional customization options available, depending on your specific needs. You can refer to the Bootstrap documentation for more information.