How to get access token and secret?

[png-prakash]

Hi,
Install this package in Laravel

public function connect(Request $request)
{
    $callbackUrl = env('APP_URL') . '/etsy/callback';
    $client = new Etsy\EtsyClient(env('ETSY_CONSUMER_KEY'), env('ETSY_CONSUMER_SECRET'));
    $helper = new Etsy\OAuthHelper($client);

    $authorizationUrl = $client->getRequestToken(
        array(
            'callback' => $callbackUrl,
            'scope' => 'transactions_r'
        )
    );

    return redirect($authorizationUrl['login_url']);
}

After connection in callback url I got like this

http://127.0.0.1:8000/etsy/callback?oauth_token=ea1d.....21&oauth_verifier=4c....5c9#_=_

In callback function, I don't know how to get access token and secret

public function callback(Request $request)
{
$client = new Etsy\OAuthHelper(env('ETSY_CONSUMER_KEY'), env('ETSY_CONSUMER_SECRET'));
}
In your document I don't see how to get access token
What is the next step?
Thanks