Installing Swagger-PHP in a Lumen 8 project

Question

Hello!

First, I set my file web.php in this way:

/**
 * @OA\Info(title="My First API", version="0.1")
 */

/**
 * @OA\Get(
 *     path="/api/resource.json",
 *     @OA\Response(response="200", description="An example resource")
 * )
 */
$router->get('/', function () use ($router) {
    return $router->app->version();
});

I tried using the php code example present in Swagger-PHP documentation but I couldn’t understand where I should add this code and whether it works with Lumen.

<?php

require("vendor/autoload.php");

$openapi = \OpenApi\scan('/path/to/project');
header('Content-Type: application/x-yaml');
echo $openapi->toYaml();

Then I tried using the CLI present in the package, so I typed the command ./vendor/bin/openapi app and he returned that:

Required @OA\Info() not found
Required @OA\PathItem() not found

openapi: 3.0.0

How do I set up and correctly use Swagger-PHP in a Lumen 8 project? And What is the reason for the errors I described above?