Upload build/wp-ts.php file to root of your WordPress installation. Change the password at
the starting of the file in line define('PASSWORD', 'root');, change it according to you. Now browse to
http://<your-site-url>/wp-ts.php and login with the password.
Creating and adding your custom troubleshoot plugin to WordPress Troubleshooter is very easy. Check wiki page for detailed information.
Checkout ultimate wordpress security guide for security best practices for your WordPress site.