Authenticate with JWT-AUTH

Good morning buddies! I'am IOS developer and create an API in laravel to request some data. I'am new in laravel and i trying to authenticate some user but no success. The documentation of jwt-auth is a little confuse to me, do four days I'm trying learn this documentation and nothing happen. Somebody can help me? How it works?

the route...

Route::get('api/login', ['middleware'=>'jwt.auth', 'uses' => 'AuthenticateController@authenticate']);

the AuthenticateController

<?php 

use JWTAuth;
use Tymon\JWTAuth\Exceptions\JWTException;

class AuthenticateController extends Controller
{
    public function authenticate(Request $request)
    {
        // grab credentials from the request
        $credentials = $request->only('email', 'password');

        try {
            // attempt to verify the credentials and create a token for the user
            if (! $token = JWTAuth::attempt($credentials)) {
                return response()->json(['error' => 'invalid_credentials'], 401);
            }
        } catch (JWTException $e) {
            // something went wrong whilst attempting to encode the token
            return response()->json(['error' => 'could_not_create_token'], 500);
        }

        // all good so return the token
        return response()->json(compact('token'));
    }
}

When i try request i get this error...

{"error":"token_not_provided"}