first upload all files

Modules/FlashSale/Resources/lang/en/attributes.php

@@ -0,0 +1,15 @@
+<?php
+
+return [
+    'product' => 'Product',
+    'end_date' => 'End Date',
+    'price' => 'Price',
+    'quantity' => 'Quantity',
+    'campaign_name' => 'Campaign Name',
+
+    // validation
+    'products.*.product_id' => 'Product',
+    'products.*.end_date' => 'End Date',
+    'products.*.price' => 'Price',
+    'products.*.qty' => 'Quantity',
+];

Modules/FlashSale/Resources/lang/en/flash_sales.php

@@ -0,0 +1,20 @@
+<?php
+
+return [
+    'flash_sale' => 'Flash Sale',
+    'flash_sales' => 'Flash Sales',
+    'table' => [
+        'campaign_name' => 'Campaign Name',
+    ],
+    'tabs' => [
+        'group' => [
+            'flash_sale_information' => 'Flash Sale Information',
+        ],
+        'products' => 'Products',
+        'settings' => 'Settings',
+    ],
+    'form' => [
+        'add_product' => 'Add Product',
+        'flash_sale_product' => 'Flash Sale Product',
+    ],
+];

Modules/FlashSale/Resources/lang/en/permissions.php

@@ -0,0 +1,8 @@
+<?php
+
+return [
+    'index' => 'Index Flash Sale',
+    'create' => 'Create Flash Sale',
+    'edit' => 'Edit Flash Sale',
+    'destroy' => 'Delete Flash Sale',
+];