Laravel Routing Route::resource inside Route::group

I am new in Laravel. routes/api.php I have written this function

Route::group(['namespace' => "Catalog"],function(){
    Route::resource('product','Product');
});

I have created a resource controller:

app/Controllers/Catalogue/Product.php

This is my index method:

public function index()
    {
        $pdo = DB::select('select count(*) from offers');
        return $pdo;
    }

I am trying to get the result from index method from url:

http://localhost:8000/api/Catalogue/product

However, this results in 404 not found. Note: There is no issue in this part of url http://localhost:8000/api

via Chebli Mohamed