Here are the steps on how to create a Facebook login app:

Go to the Facebook Developers: https://developers.facebook.com/ website and log in to your account.
Click on the My Apps tab.
Click on the Create App button.
Enter the name of your app and your email address.
Select the platform that your app will run on.
Click on the Create App ID button.
Click on the Facebook Login tab.
Click on the Set Up button.
Select the platform that your app will run on.
Enter the website URL for your app.
Click on the Save Changes button.
Once you have created your Facebook login app, you will need to configure it in your app. This process will vary depending on the platform that your app is running on.

Here are some resources that you can use to learn more about creating and configuring a Facebook login app:

Facebook Login Documentation: https://developers.facebook.com/docs/facebook-login/
Facebook Login for Web: https://developers.facebook.com/docs/facebook-login/web
Facebook Login for Android: https://developers.facebook.com/docs/facebook-login/android
Facebook Login for iOS: https://developers.facebook.com/docs/facebook-login/ios
I hope this helps! Let me know if you have any other questions