Twig not working in Yii2 - php

Question

I want to use Twig in Yii2 framework but it isn't working.
I am using yii2-app-advanced as the base project but I am new in the Yii world so I think I am not configuring Twig in the right way.
First I downloaded it using:
composer require yiisoft/yii2-twig
Then I follow this instructions but it's not easy to understand:
https://github.com/yiisoft/yii2-twig/blob/HEAD/docs/guide/installation.md#configuring-application
It says:
In order to start using Twig you need to configure view component like the following:
[
'components' => [
'view' => [
'class' => 'yii\web\View',
'renderers' => [
'twig' => [
'class' => 'yii\twig\ViewRenderer',
'cachePath' => '#runtime/Twig/cache',
// Array of twig options:
'options' => [
'auto_reload' => true,
],
'globals' => [
'html' => ['class' => '\yii\helpers\Html'],
],
'uses' => ['yii\bootstrap'],
],
// ...
],
],
],
]
In which file I have to paste this code?
In my index.php file I added the following code but it is not working:
{% if true %}
<p>It is true.</p>
{% else %}
<p>It is false.</p>
{% endif %}

Answer 1

I solved it doing this:
I modified the file backend/config/main-local-php:
<?php
$config = [
'components' => [
'request' => [
// !!! insert a secret key in the following (if it is empty) - this is required by cookie validation
'cookieValidationKey' => 'CPeTotdTU98geIyM7q0PljmCpJbupPN4',
],
'view' => [
'class' => 'yii\web\View',
'renderers' => [
'twig' => [
'class' => 'yii\twig\ViewRenderer',
'cachePath' => '#runtime/Twig/cache',
// Array of twig options:
'options' => [
'auto_reload' => true,
],
'globals' => [
'html' => ['class' => '\yii\helpers\Html'],
],
'uses' => ['yii\bootstrap'],
],
// ...
],
],
],
];
if (!YII_ENV_TEST) {
// configuration adjustments for 'dev' environment
$config['bootstrap'][] = 'debug';
$config['modules']['debug'] = [
'class' => 'yii\debug\Module',
];
$config['bootstrap'][] = 'gii';
$config['modules']['gii'] = [
'class' => 'yii\gii\Module',
];
}
return $config;
The SiteController.php file has the actionIndex() function. I added the extension .twig:
public function actionIndex()
{
return $this->render('index.twig');
}
And then I modified the name of the file backend/views/sire/index.php to index.twig.