diff --git a/docs/outline/chapter5.md b/docs/outline/chapter5.md
index cc444c2..c891546 100644
--- a/docs/outline/chapter5.md
+++ b/docs/outline/chapter5.md
@@ -5,7 +5,52 @@ flutter pub add firebase_core
 flutter pub add cloud_firestore
 ```
 
-[GitHub Discussions](https://github.com/FlutterKaigi/tic_tac_toe_handson/discussions) から `firebase-options.dart` を取得し、Libに追加します。
+`firebase_options.dart` をLibに追加します。
+
+```dart
+// ignore_for_file: lines_longer_than_80_chars, avoid_classes_with_only_static_members
+import 'package:firebase_core/firebase_core.dart' show FirebaseOptions;
+import 'package:flutter/foundation.dart'
+    show defaultTargetPlatform, kIsWeb, TargetPlatform;
+
+class DefaultFirebaseOptions {
+  static FirebaseOptions get currentPlatform {
+    if (kIsWeb) {
+      throw UnsupportedError(
+        'DefaultFirebaseOptions have not been configured for web - '
+            'you can reconfigure this by running the FlutterFire CLI again.',
+      );
+    }
+    switch (defaultTargetPlatform) {
+      case TargetPlatform.android:
+        return android;
+      case TargetPlatform.iOS:
+        return ios;
+      default:
+        throw UnsupportedError(
+          'DefaultFirebaseOptions are not supported for this platform.',
+        );
+    }
+  }
+
+  static const FirebaseOptions android = FirebaseOptions(
+    apiKey: 'AIzaSyCCWnRieFsedimIvgsjNevAdUSb0dm1faY',
+    appId: '1:807943088200:android:d989c8a1b020562321907d',
+    messagingSenderId: '807943088200',
+    projectId: 'tic-tac-toe-handson',
+    storageBucket: 'tic-tac-toe-handson.appspot.com',
+  );
+
+  static const FirebaseOptions ios = FirebaseOptions(
+    apiKey: 'AIzaSyBZHELrAr4SRfXLYrxc4zF27P0R3sGsbi0',
+    appId: '1:807943088200:ios:125d7bfaa751582d21907d',
+    messagingSenderId: '807943088200',
+    projectId: 'tic-tac-toe-handson',
+    storageBucket: 'tic-tac-toe-handson.appspot.com',
+    iosBundleId: 'com.example.ticTacToeHandson',
+  );
+}
+```
 
 次に `main.dart` を修正します。
 ```dart
@@ -40,7 +85,7 @@ classpath 'com.google.gms:google-services:4.3.10'
 ```
 
 ### 2. iOSでのビルド準備を進める
-iOSフォルダをXcodeで開いたのちに、Runnerに`google-services.json` を追加します。  
+iOSフォルダをXcodeで開いたのちに、Runnerに[GitHub Discussions](https://github.com/FlutterKaigi/tic_tac_toe_handson/discussions) で取得した  `GoogleService-Info.plist` を追加します。  
 このとき、「Copy items if needed」にチェックを入れて追加してください。
 
 ![Alt text](../public/chapter5/add_plist.png)