first upload all files

Modules/FlashSale/Providers/FlashSaleServiceProvider.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace Modules\FlashSale\Providers;
+
+use Modules\Support\Traits\AddsAsset;
+use Illuminate\Support\ServiceProvider;
+use Modules\Admin\Ui\Facades\TabManager;
+use Modules\FlashSale\Admin\FlashSaleTabs;
+
+class FlashSaleServiceProvider extends ServiceProvider
+{
+    use AddsAsset;
+
+    /**
+     * Bootstrap the application services.
+     *
+     * @return void
+     */
+    public function boot()
+    {
+        TabManager::register('flash_sales', FlashSaleTabs::class);
+
+        $this->addAdminAssets('admin.flash_sales.(create|edit)', ['admin.media.js', 'admin.flashsale.js']);
+    }
+}