I am going through the M-V-C architecture in PHP programming and having some confusion in core part, will someone can help me to understand it?

I have just start with the M-V-C pattern programming and learn a new code. Here I have some confusion will some one help me out.

Below is the code:-

<?php

class Model { public $string; public function __construct() { $this->string = Lets start php with MVC; } } ?> I understand the class declaration, data members declaration(variables), methods/functions in class. But I got stuck here "$this->string = Lets start php with MVC;". What is the meaning of this line please explain in brief with clarification in simple manners.   Note: I am just start and beginner in M-V-C pattern. Please give me some simple word solution so, I can understand it easily.   Best Regards,