Deploying an advanced project template to shared hosting is a bit trickier than a basic one because it has two webroots, which shared hosting webservers don't support. We will need to adjust the directory structure so frontend URL will be http://site.local and backend URL will be http://site.local/admin.

Move entry scripts into single webroot

First of all we need a webroot directory. Create a new directory and name it to match your hosting webroot name, e.g., www or public_html or the like. Then create the following structure where www is the hosting webroot directory you just created:

www
    admin
backend
common
console
environments
frontend
...

www will be our frontend directory so move the contents of frontend/web into it. Move the contents of backend/web into www/admin. In each case you will need to adjust the paths in index.php and index-test.php.

Adjust sessions and cookies

Originally the backend and frontend are intended to run at different domains. When we’re moving it all to the same domain the frontend and backend will be sharing the same cookies, creating a clash. In order to fix it, adjust backend application config backend/config/main.php as follows:

'components' => [
    'request' => [
        'csrfParam' => '_csrf-backend',
        'csrfCookie' => [
            'httpOnly' => true,
            'path' => '/admin',
        ],
    ],
    'user' => [
        'identityClass' => 'common\models\User',
        'enableAutoLogin' => true,
        'identityCookie' => [
            'name' => '_identity-backend',
            'path' => '/admin',
            'httpOnly' => true,
        ],
    ],
    'session' => [
        // this is the name of the session cookie used for login on the backend
        'name' => 'advanced-backend',
        'cookieParams' => [
            'path' => '/admin',
        ],
    ],
],

Hope this helps for the shared hosting users to deploy advanced application.

credits : https://github.com/yiisoft/yii2-app-advanced/blob/master/docs/guide/topic-shared-hosting.md

So you've uploaded your files to a folder say /backend/web/uploads/ and you want these uploads to be visible on the frontend too. The easiest option is to create a symlink in the frontend that links to the backend:

ln -s /path/to/backend/web/uploads/ /path/to/frontend/web/uploads

In your views you can use relative links to the files now:

<img src='/uploads/<?= $model->image?>' alt='My Image goes here'>
<a href='/uploads/<?= $model->filename?>' target='_blank'>Download File</a>

Ensure that your webserver allows symlinks to be followed.