Laravel 3 : Looking for explanation how to use the model

The best statement on the subject of Frameworks I've heard is due to Uncle Bob:

A good Architecture allows major decisions to be deferred!

Specifically:

  • A good Architecture delays choosing a Framework!

Another great piece to think about:

MVC is not an Architecture! It is a Delivery Design Pattern.

Watch his video - it is one of the sadly few ones out there that don't spend 1000 words on what can be said in 10 and I can't highly enough recommend it - and it will help you to understand many points raised in your question:

Robert C Martin(Uncle Bob) -Clean Architecture and Design - Video

Of course, his book on Clean Code is also highly recommended!