Getting Confusion of Using Variables and Conditionals

A variable could be compared to a box where you stock something. And to put something in the variable you need to use the equal sign. It's not at all a comparison. So as exemple $AmountOfMoney = 2000; means I've 'justed assigned/stored 2000 to my variable $AmountOfMoney.

But as the equal sign is used to assign a value to a variable, how can you compare two variables ? Obviously not using an equal sign as It's already used to store information. So you to use two equal sign such as '=='

Another little exemple:

<?php
        $cars = "four wheels";
        $motorcycles = "two wheels";  // as you can see I'm assigning values to some variables, at this stage.
         // And $cars has the value four wheels at the moment, $motorcycles, two wheels.

        $cars = $motorcyles    // I'm not doing a comparison here, I'm putting the value of $motorcycles into $cars, which means $cars isn't equal to "four wheels" anymore but has the value of "two wheels".

       $cars == $motorcyles       //I'm not assigning anything, I'm comparing, and $cars == $motorcycles is now TRUE, as they both have the same   value which is "two wheels".
?>

It's just something you have to remember... "=" doesn't mean equal to when you code but more something like, "contains" while "==" means really equal to.