[
     ...
     'layout' => 'main',
     'components' => [
     ...
     ]
]

$config = [
    ...

    'layoutPath' => '@app/views/layouts-2'
];

<?php $this->beginContent('@app/views/layouts/main.php'); ?>
    <div class="container">
        <div class="row">
            <div class="col-lg-4">Left Side Bar</div>

            <div id="content" class="col-lg-4">
                <?php echo $content; ?>
            </div><!-- content -->

            <div class="col-lg-4">Right Side Bar</div>
        </div>
    </div>
<?php $this->endContent(); ?>

public function actionIndex()
{
    $this->layout = 'defaultLayout';

    return $this->render('index', [
        'model' =>$model,
    ]);
}

[
    // ...
    'components' => [
        'view' => [
            'layout' => 'main.php'
        ],
        // ...
    ],
]

$config = [
    ...
    'layoutPath' => '@app/views/layouts2',
    'layout' => 'main2.php',
];

'layout' => 'main_style'