$csrfToken = 'csrf-token';
$url = (new AuthCodeGrant('your-client-id', 'your-secret-key', 'your-callback-url))->getConfirmPageUrl($csrfToken);

// handle callback request

$state = $_GET['state'] ?? null; // this should be same as CSRF token you set to AuthCodeGrant::getConfirmPageUrl() 
$code = $_GET['code'] ?? null; // handle error if $code is null
$accessToken = $grant->requestAccessToken($code, new AppExecutor('your-client-id', 'your-secret-key'));

// GET /verify_credentials
$accessTokenEntity = new AccessToken('access-token');
$executor = new UserExecutor($accessTokenEntity);
$response = $executor->get("verify_credentials");
$userInfo = json_decode($response->getBody()->getContents(), true);

// POST /movies/:movie_id/comments
$movieId = 1234;
$response = $executor->post("movies/{$movieId}/comments", ['comment' => 'hello!!']);

// GET /users/twitcasting/jp

$executor = new AppExecutor('your-client-id', 'your-secret-key');
$response = $executor->get("users/twitcasting_jp");
$userInfo = json_decode($response->getBody()->getContents(), true);