Show notifications with objective c

I'm making an application in objective C to show Firebase notifications link and I've I managed to receive and display the messages by console, I tried to appear in the notification tray of iOS but it does not come out.

I have tried several things but since I have no experience with objective C I am a bit lost, any help?

AppDelegate.m

//
//  Copyright (c) 2016 Google Inc.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//

#import "AppDelegate.h"

#if defined(__IPHONE_10_0) && __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_10_0
@import UserNotifications;
#endif

@import Firebase;

// Implement UNUserNotificationCenterDelegate to receive display notification via APNS for devices
// running iOS 10 and above. Implement FIRMessagingDelegate to receive data message via FCM for
// devices running iOS 10 and above.
#if defined(__IPHONE_10_0) && __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_10_0
@interface AppDelegate () <UNUserNotificationCenterDelegate, FIRMessagingDelegate>
@end
#endif

// Copied from Apple's header in case it is missing in some cases (e.g. pre-Xcode 8 builds).
#ifndef NSFoundationVersionNumber_iOS_9_x_Max
#define NSFoundationVersionNumber_iOS_9_x_Max 1299
#endif

@implementation AppDelegate

NSString *const kGCMMessageIDKey = @"gcm.message_id";

- (BOOL)application:(UIApplication *)application
didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    // Register for remote notifications. This shows a permission dialog on first run, to
    // show the dialog at a more appropriate time move this registration accordingly.
    if (floor(NSFoundationVersionNumber) <= NSFoundationVersionNumber_iOS_7_1) {
        // iOS 7.1 or earlier. Disable the deprecation warnings.
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
        UIRemoteNotificationType allNotificationTypes =
        (UIRemoteNotificationTypeSound |
         UIRemoteNotificationTypeAlert |
         UIRemoteNotificationTypeBadge);
        [application registerForRemoteNotificationTypes:allNotificationTypes];
#pragma clang diagnostic pop
    } else {
        // iOS 8 or later
        // [START register_for_notifications]
        if (floor(NSFoundationVersionNumber) <= NSFoundationVersionNumber_iOS_9_x_Max) {
            UIUserNotificationType allNotificationTypes =
            (UIUserNotificationTypeSound | UIUserNotificationTypeAlert | UIUserNotificationTypeBadge);
            UIUserNotificationSettings *settings =
            [UIUserNotificationSettings settingsForTypes:allNotificationTypes categories:nil];
            [[UIApplication sharedApplication] registerUserNotificationSettings:settings];
        } else {
            // iOS 10 or later
#if defined(__IPHONE_10_0) && __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_10_0
            // For iOS 10 display notification (sent via APNS)
            [UNUserNotificationCenter currentNotificationCenter].delegate = self;
            UNAuthorizationOptions authOptions =
            UNAuthorizationOptionAlert
            | UNAuthorizationOptionSound
            | UNAuthorizationOptionBadge;
            [[UNUserNotificationCenter currentNotificationCenter] requestAuthorizationWithOptions:authOptions completionHandler:^(BOOL granted, NSError * _Nullable error) {
            }];

            // For iOS 10 data message (sent via FCM)
            [FIRMessaging messaging].remoteMessageDelegate = self;
#endif
        }

        [[UIApplication sharedApplication] registerForRemoteNotifications];
        // [END register_for_notifications]
    }

    // [START configure_firebase]
    [FIRApp configure];
    // [END configure_firebase]
    // [START add_token_refresh_observer]
    // Add observer for InstanceID token refresh callback.
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(tokenRefreshNotification:)
                                                 name:kFIRInstanceIDTokenRefreshNotification object:nil];
    // [END add_token_refresh_observer]
    return YES;
}

// [START receive_message]
- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo {
    // If you are receiving a notification message while your app is in the background,
    // this callback will not be fired till the user taps on the notification launching the application.
    // TODO: Handle data of notification

    // Print message ID.
    if (userInfo[kGCMMessageIDKey]) {
        NSLog(@"Message ID: %@", userInfo[kGCMMessageIDKey]);
    }

    // Print full message.
    NSLog(@"%@", userInfo);
}

- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo
fetchCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler {
    // If you are receiving a notification message while your app is in the background,
    // this callback will not be fired till the user taps on the notification launching the application.
    // TODO: Handle data of notification

    // Print message ID.
    if (userInfo[kGCMMessageIDKey]) {
        NSLog(@"Message ID: %@", userInfo[kGCMMessageIDKey]);
    }

    // Print full message.
    NSLog(@"%@", userInfo);

    completionHandler(UIBackgroundFetchResultNewData);
}
// [END receive_message]

// [START ios_10_message_handling]
// Receive displayed notifications for iOS 10 devices.
#if defined(__IPHONE_10_0) && __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_10_0
// Handle incoming notification messages while app is in the foreground.
- (void)userNotificationCenter:(UNUserNotificationCenter *)center
       willPresentNotification:(UNNotification *)notification
         withCompletionHandler:(void (^)(UNNotificationPresentationOptions))completionHandler {
    // Print message ID.
    NSDictionary *userInfo = notification.request.content.userInfo;
    if (userInfo[kGCMMessageIDKey]) {
        NSLog(@"Message ID: %@", userInfo[kGCMMessageIDKey]);
    }

    // Print full message.
    NSLog(@"%@", userInfo);

    // Change this to your preferred presentation option
    completionHandler(UNNotificationPresentationOptionNone);
}

// Handle notification messages after display notification is tapped by the user.
- (void)userNotificationCenter:(UNUserNotificationCenter *)center
didReceiveNotificationResponse:(UNNotificationResponse *)response
         withCompletionHandler:(void (^)())completionHandler {
    NSDictionary *userInfo = response.notification.request.content.userInfo;
    if (userInfo[kGCMMessageIDKey]) {
        NSLog(@"Message ID: %@", userInfo[kGCMMessageIDKey]);
    }

    // Print full message.
    NSLog(@"%@", userInfo);

    completionHandler();
}
#endif
// [END ios_10_message_handling]

// [START ios_10_data_message_handling]
#if defined(__IPHONE_10_0) && __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_10_0
// Receive data message on iOS 10 devices while app is in the foreground.
- (void)applicationReceivedRemoteMessage:(FIRMessagingRemoteMessage *)remoteMessage {
    // Print full message
    NSLog(@"%@", remoteMessage.appData);
}
#endif
// [END ios_10_data_message_handling]

// [START refresh_token]
- (void)tokenRefreshNotification:(NSNotification *)notification {
    // Note that this callback will be fired everytime a new token is generated, including the first
    // time. So if you need to retrieve the token as soon as it is available this is where that
    // should be done.
    NSString *refreshedToken = [[FIRInstanceID instanceID] token];
    NSLog(@"InstanceID token: %@", refreshedToken);

    // Connect to FCM since connection may have failed when attempted before having a token.
    [self connectToFcm];

    // TODO: If necessary send token to application server.
}
// [END refresh_token]

// [START connect_to_fcm]
- (void)connectToFcm {
    // Won't connect since there is no token
    if (![[FIRInstanceID instanceID] token]) {
        return;
    }

    // Disconnect previous FCM connection if it exists.
    [[FIRMessaging messaging] disconnect];

    [[FIRMessaging messaging] connectWithCompletion:^(NSError * _Nullable error) {
        if (error != nil) {
            NSLog(@"Unable to connect to FCM. %@", error);
        } else {
            NSLog(@"Connected to FCM.");
        }
    }];
}
// [END connect_to_fcm]

- (void)application:(UIApplication *)application didFailToRegisterForRemoteNotificationsWithError:(NSError *)error {
    NSLog(@"Unable to register for remote notifications: %@", error);
}

// This function is added here only for debugging purposes, and can be removed if swizzling is enabled.
// If swizzling is disabled then this function must be implemented so that the APNs token can be paired to
// the InstanceID token.
- (void)application:(UIApplication *)application didRegisterForRemoteNotificationsWithDeviceToken:(NSData *)deviceToken {
    NSLog(@"APNs token retrieved: %@", deviceToken);

    // With swizzling disabled you must set the APNs token here.
    // [[FIRInstanceID instanceID] setAPNSToken:deviceToken type:FIRInstanceIDAPNSTokenTypeSandbox];
}

// [START connect_on_active]
- (void)applicationDidBecomeActive:(UIApplication *)application {
    [self connectToFcm];
}
// [END connect_on_active]

// [START disconnect_from_fcm]
- (void)applicationDidEnterBackground:(UIApplication *)application {
    [[FIRMessaging messaging] disconnect];
    NSLog(@"Disconnected from FCM");
}
// [END disconnect_from_fcm]

@end

I have looked at this tutorial link and I added the code to create a notification in the event of receiving the message, but I get an error when compiling:

// Receive data message on iOS 10 devices while app is in the foreground.
    - (void)applicationReceivedRemoteMessage:(FIRMessagingRemoteMessage *)remoteMessage {
        // Print full message
        NSLog(@"%@", remoteMessage.appData);


        UNMutableNotificationContent* content = [[UNMutableNotificationContent alloc] init];
        content.title = [NSString localizedUserNotificationStringForKey:@"Hello!" arguments:nil];
        content.body = [NSString localizedUserNotificationStringForKey:@"Hello_message_body"
                                                             arguments:nil];
        content.sound = [UNNotificationSound defaultSound];

        // Deliver the notification in five seconds.
        UNTimeIntervalNotificationTrigger* trigger = [UNTimeIntervalNotificationTrigger
                                                      triggerWithTimeInterval:5 repeats:NO];
        UNNotificationRequest* request = [UNNotificationRequest requestWithIdentifier:@"FiveSecond"
                                                                              content:content trigger:trigger];

        // Schedule the notification.
        UNUserNotificationCenter* center = [UNUserNotificationCenter currentNotificationCenter];
        [center addNotificationRequest:request completionHandler:nil];
    }

I miss compiling:

/Users/ubiquat/projectes/Notificacions/Notificacions/AppDelegate.m:190:13: No visible @interface for 'UNUserNotificationCenter' declares the selector 'addNotificationRequest:completionHandler:'