Suitecrm 8.2 Static Menu Nav Bar

I am creating an application in suitecrm 8.2.3.

I need to add a static menu (multi-level dropdown ) instead of the default menu and add some external links also in that menu.

I have tried the following solution

  1. tried to create a global js file.
  2. created file in the root directory and added the path in config_override.php
    $sugar_config[‘externalScripts’][‘custom’] = array(
    ‘file’ => ‘custom/scripts/custom.js’,
    but the custom js file is not loaded.

Any Suggestion