Do you think everything was written from scratch
Yes
Laravel is a php framework, with many things like Auth built in.
But it is not a CMS.
Think about this. Once you program in your CRUD, what do you basically have? A cms in a way.
You should pay for a month and view the let's build a blog series, it will give you an idea. Or at least view
https://laracasts.com/series/laravel-from-scratch-2017 FREE
Edit
I see you are new here,