A couple of things I don't quite understand about Twig

This might be quite long winded but I'll try and keep it as concise as I can. I've just finished the Twig course and instead of following along 100% of the course I made for myself an (albeit small and ugly) site for myself which is almost working except for 1 important thing. The routing doesn't work and I'm not sure why.

So

• Not sure why the routing is not working
• Why we need 2 sets of content blocks for each portion of the site

Here's my controller index.php file where routing is made.

<?php 

//path to the composer vendor file
require_once __DIR__. '/../vendor/autoload.php';

//render index template to same file
/* $loader = new \Twig\Loader\ArrayLoader([
    'index' => 'Hello {{ name }}!',
]); */


//render a directory template
$loader = new \Twig\Loader\FilesystemLoader( __DIR__ . '/../templates');
$twig = new \Twig\Environment($loader);


//an array for navigation
$nav = [
    'home' => [
        'href' => '/jgdm-100daysofcode/php/twig/public/',
        'caption' => 'Welcome',
        'status' => 'false'
    ],
    'contact' => [
        'href' => '/jgdm-100daysofcode/php/twig/public/contact',
        'caption' => 'Contact Us',
        'status' => false
    ]

];

// Routing  - routing is not showing contact.twig on click.
if (substr($_SERVER['REQUEST_URI'], 0, 8) == '/contact') {
    $nav['contact']['status'] = "active";
    echo $twig->render('contact.twig', array('name'=>'jonnie', 'nav' => $nav, 'post' => $_POST));
} else {
    $nav['home']['status'] = "active";
    echo $twig->render('home.twig', array('name'=> 'jonnie', 'nav' => $nav));
}

//specify a template or a file to render
//echo $twig->render('home.twig', ['name' => 'jonnie', 'nav' => $nav]);
//echo $twig->render('home.twig', array('navigation'=>$nav, 'nav' => $nav));

?>

Secondly, I have a question about content blocks in Twig. I don't understand why we need so many duplicates of the content blocks. e.g.

{% block footer %}
{% endblock %}

Why can't we define it in base or home.twig and define the content in individual files?

Let's use the project footer as an example. In my project, I have 3 sets of content blocks for the footer.

{% block footer %}
{% endblock %}

This is an empty content block. It's where I'd ideally like to put the HTML content for the footer.

{% block footer %}
{% endblock %}

Also an empty content block.

{% block footer %}
    <footer>
        <p>&copy; {{ "now"|date('Y') }} Jonnie Grieve Digital Media</p>
    </footer>

    </body>
    </html>

{% endblock %}

This is where the content for the header currently lives. But if I put this in footer.twig it disappears despite the fact the block is defined in base.twig. I don't know if it's anything I've done wrong but the way this is structured doesn't seem right.

If you want to have a closwer look, you'll find the project in php/twig directory of this repository on GitHub. https://github.com/jg-digital-media/jgdm-100DaysOfCode