diff --git a/app/Http/Controllers/ChapterController.php b/app/Http/Controllers/ChapterController.php
index c1df102..3deaae3 100644
--- a/app/Http/Controllers/ChapterController.php
+++ b/app/Http/Controllers/ChapterController.php
@@ -10,9 +10,13 @@ class ChapterController extends Controller
     public function index(Chapter $chapter, SymfonyCastDlService $symfonyCastDlService)
     {
         $symfonyCastDlService->videoSize($chapter);
-        if($chapter->sync_offline){
+        if ($chapter->sync_offline) {
             $symfonyCastDlService->downloadFile($chapter);
         }
-        return view('chapter.index', compact('chapter'));
+        $chapters = $chapter->course->chapters;
+
+        $next = $chapters->where('order', '>', $chapter->order)->first();
+        $prev = $chapters->where('order', '<', $chapter->order)->sortByDesc('order')->first();
+        return view('chapter.index', compact('chapter', 'chapters', 'prev', 'next'));
     }
 }
diff --git a/app/Models/Chapter.php b/app/Models/Chapter.php
index 341b9ff..031e218 100644
--- a/app/Models/Chapter.php
+++ b/app/Models/Chapter.php
@@ -36,13 +36,20 @@ class Chapter extends Model
         'sync_offline',
     ];
 
-    protected $appends = ['video_path', 'directory_path'];
+    protected $appends = ['video_path', 'directory_path', 'video_url'];
 
     public function course(): BelongsTo
     {
         return $this->belongsTo(Course::class);
     }
 
+    protected function videoUrl(): Attribute
+    {
+        return Attribute::make(
+            get: fn() => url($this->course_id . '/' . $this->order . '.mp4')
+        );
+    }
+
     protected function videoPath(): Attribute
     {
         return Attribute::make(
@@ -68,9 +75,7 @@ class Chapter extends Model
     {
         return Attribute::make(
             get: function () {
-                $base = log($this->video_size) / log(1024);
-                $suffix = ["", "k", "M", "G", "T"][floor($base)];
-                return round(pow(1024, $base - floor($base)), 2) . $suffix;
+                return formatFileSize($this->video_size);
             },
         );
     }
diff --git a/app/Models/Course.php b/app/Models/Course.php
index 9feae52..bd4f0cd 100644
--- a/app/Models/Course.php
+++ b/app/Models/Course.php
@@ -33,6 +33,7 @@ class Course extends Model
         'published_at',
     ];
 
+    protected $appends = ['total_size', 'total_size_human'];
     protected $dates = [
         'published_at'
     ];
@@ -53,9 +54,7 @@ class Course extends Model
     {
         return Attribute::make(
             get: function () {
-                $base = log($this->total_size) / log(1024);
-                $suffix = ["", "k", "M", "G", "T"][floor($base)];
-                return round(pow(1024, $base - floor($base)), 2) . $suffix;
+                return formatFileSize($this->total_size);
             },
         );
     }
diff --git a/app/helpers.php b/app/helpers.php
new file mode 100644
index 0000000..fd45259
--- /dev/null
+++ b/app/helpers.php
@@ -0,0 +1,22 @@
+<?php
+
+if (!function_exists('formatFileSize')) {
+    function formatFileSize($fileSizeInBytes): string
+    {
+        $base = log($fileSizeInBytes) / log(1024);
+        $suffix = ["", "k", "M", "G", "T"][floor($base)];
+        $size = round(pow(1024, $base - floor($base)), 2);
+        return !is_nan($size) ? $size . $suffix : '0B';
+    }
+}
+
+if (!function_exists('folderSize')) {
+    function folderSize($dir): int
+    {
+        $size = 0;
+        foreach (glob(rtrim($dir, '/') . '/*', GLOB_NOSORT) as $each) {
+            $size += is_file($each) ? filesize($each) : folderSize($each);
+        }
+        return $size;
+    }
+}
diff --git a/composer.json b/composer.json
index 82c48fd..9a93e75 100644
--- a/composer.json
+++ b/composer.json
@@ -2,7 +2,10 @@
     "name": "laravel/laravel",
     "type": "project",
     "description": "The Laravel Framework.",
-    "keywords": ["framework", "laravel"],
+    "keywords": [
+        "framework",
+        "laravel"
+    ],
     "license": "MIT",
     "require": {
         "php": "^8.0.2",
@@ -27,7 +30,10 @@
             "App\\": "app/",
             "Database\\Factories\\": "database/factories/",
             "Database\\Seeders\\": "database/seeders/"
-        }
+        },
+        "files": [
+            "app/helpers.php"
+        ]
     },
     "autoload-dev": {
         "psr-4": {
diff --git a/resources/views/chapter/index.blade.php b/resources/views/chapter/index.blade.php
index 4f4fc5e..ef4bb9a 100644
--- a/resources/views/chapter/index.blade.php
+++ b/resources/views/chapter/index.blade.php
@@ -1,14 +1,26 @@
 <x-layout>
     <h1>
-        {{ $chapter->course->name }}
+        <a href="/">List</a> &raquo; <a
+            href="{{ route('course.index', ['course' => $chapter->course_id]) }}">{{ $chapter->course->name }}</a>
         <br>
         <small class="text-muted">{{ $chapter->title }}</small>
     </h1>
     <div>
+        <div class="float-none">
+            @if($prev)
+                <div class="float-start m-2"><a href="{{ route('course.chapter', ['chapter' => $prev->id]) }}">Prev</a>
+                </div>
+            @endif
+            @if($next)
+                <div class="float-end m-2"><a href="{{ route('course.chapter', ['chapter' => $next->id]) }}">Next</a>
+                </div>
+            @endif
+        </div>
+
         <div class="mx-auto" style="width: 500px;">
             @if($chapter->is_video_file)
                 <video class="mx-auto" width="500" controls>
-                    <source src="/{{ $chapter->video_path }}" type="video/mp4"/>
+                    <source src="{{ $chapter->video_url }}" type="video/mp4"/>
                 </video>
             @endif
         </div>
diff --git a/resources/views/index.blade.php b/resources/views/index.blade.php
index 67b0ace..8ae8c84 100644
--- a/resources/views/index.blade.php
+++ b/resources/views/index.blade.php
@@ -9,17 +9,35 @@
             <th>status</th>
             <th>Chapters</th>
             <th>Published at</th>
+            <th>Estimate file size</th>
+            <th>Actual size</th>
         </tr>
         </thead>
         @foreach($courses as $course)
             <tr>
                 <td class="align-middle">{{ $course->id }}</td>
-                <td><img src="{{ $course->thumbnail }}" alt="{{ $course->name }}" class="img-thumbnail" style="width: 70px;"></td>
-                <td class="align-middle"><a href="{{ route('course.index', ['course' => $course->id]) }}">{{ $course->name }}</a></td>
+                <td><img src="{{ $course->thumbnail }}" alt="{{ $course->name }}" class="img-thumbnail"
+                         style="width: 70px;"></td>
+                <td class="align-middle"><a
+                        href="{{ route('course.index', ['course' => $course->id]) }}">{{ $course->name }}</a></td>
                 <td class="align-middle">{{ $course->status }}</td>
                 <td class="align-middle">{{ $course->chapters_count }} / {{ $course->numberofchapters }}</td>
-                <td class="align-middle"><abbr title="{{ $course->published_at?->format('Y-m-d') }}">{{ $course->published_at?->diffForHumans() }}</abbr></td>
+                <td class="align-middle"><abbr
+                        title="{{ $course->published_at?->format('Y-m-d') }}">{{ $course->published_at?->diffForHumans() }}</abbr>
+                </td>
+                <td class="align-middle text-end pe-4">{{ $course->total_size_human }}</td>
+                <td class="align-middle text-end pe-4">{{formatFileSize(folderSize(public_path($course->id)))}}</td>
             </tr>
         @endforeach
+        <tr>
+            <td></td>
+            <td></td>
+            <td></td>
+            <td></td>
+            <td></td>
+            <td></td>
+            <td class="align-middle text-end pe-4">{{ formatFileSize($courses->sum('total_size')) }}</td>
+            <td class="align-middle text-end pe-4">{{formatFileSize(folderSize(public_path()))}}</td>
+        </tr>
     </table>
 </x-layout>