Authorization, authentication in Laravel 5.1, I can't figure out how it works?

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User identification

Hello! Please do not kick me if my questions seem childish and / or too simple to someone. I don't have much experience in php programming, but I'm very interested in learning it. I know the basics (OOP, MVC, working with the database, etc., worked a little with CodeIgniter) I recently started learning Laravel, and immediately got into a dead end. I ask anyone to shed some light on a few points regarding authorization / authentication:
1. What are the names of the methods for authorization which (as I understand it) must be overridden so that they overlap the methods from the trait?
2. Do you need to override these methods in AuthController?
3. Where to specify which fields are needed to enter? For example, I need not only by login and password, but also the user must enter his personal code.
4. How/Where is the validation of the entered data carried out?
5, How to redirect in case of successful authorization?
6. How does Laravel determine if the user is authorized or not? (Auth::check() what does this method check? cookie? session? or something else?)
Fuh .... It seems that's all for now :)
Who is not difficult, comment, please, my questions, and if someone gives a ready-made controller with views and a model, I will be very grateful! Ready I ask not because I'm lazy, but I just can't figure it out.
Thanks in advance.