Is there any other ways to solve this PostsController not working on Laravel 8? [duplicate]

I'm new learning Laravel. I following a tutorial on Laravel 5.2 where using PostsController. I followed the method, I comment out all code in routes/web.php and put on Route::get('/post','PostsController@index'); line. then I edited the PostsController file and put this "its working" inside the index function. public function index() { return "its working"; } Not showing the line in screen. but showing errors.

C:\xampp\htdocs\blog
Illuminate\Contracts\Container\BindingResolutionException Target class [PostsController] does not exist. http://127.0.0.1:8000/post

What should I do now ? Any solution and any other way ?

Here's the error screenshot

via Chebli Mohamed