Hi, 

I'm trying to use bootstrap components in my plugin but I can't. I just want to create an empty page with an alert box and a button in it (user is redirected to this page after form submission then redirected back using the button).

I believe I didn't import the bootstrap, but how do I do that, I'm still new to moodle development so I don't know what to do at all.

Here is my code:

require_once(dirname(__FILE__) . '/../../config.php');

defined('MOODLE_INTERNAL') || die;

global $PAGE, $CFG;

$reurl = new moodle_url('/blocks/progress_report/overview.php', array('courseid' => $params['courseid'],

                                        'instanceid' => $params['instanceid'], 'sesskey' => $params['sesskey']

));

echo html_writer::start_tag('div', array('class' => 'alert alert-warning alert-dismissible fade show',

                                         'role' => 'alert'));

echo 'Grade Updated Successfully';

echo html_writer::start_tag('button', array('type' => 'button','class' => 'close', 'data-dismiss'=>'alert' , 'aria-label'=>'close'));

echo html_writer::start_tag('span', array('aria-hidden' => 'true'));

echo '×';

echo html_writer::end_tag('span');

echo html_writer::end_tag('button');

echo html_writer::end_tag('div');

echo html_writer::start_tag('a', array('id' => 'redirect','href' => $reurl));

echo 'Go Back';

echo html_writer::end_tag('a');