Follow Laravel Filemanager installation guide here https://unisharp.github.io/laravel-filemanager/installation. (recommend version 1.9.2 or below because after this version still have a problem with auth middlewares and I don't know how to fix it)
Open /config/lfm.php and add your own assets path for your icon example
'assets_directory' => '/themes/[your_theme_name]/assets',
remove 'auth' config in middlewares option.
middlewares' => ['web'],