After installing the module, you can enable any individual field in any CRUD to be "searchable":
And then, in the generated panel, in top-left corner, you will see a search field, which, after you type in at least 3 characters, will look for all records in all CRUDs/Fields you specified:
Customization
If you want to customize the behavior of Global Search, it's all in the generated file app/Http/Controllers/Admin/GlobalSearchController.php, here's the main method: