I have setup subdomains properly in linode dns manager and also setup in sites-available in ubuntu 14, but my subdomain is not working. Can you guys help, how to set up wordpress subdomain in nginx with ubuntu 14?

I have tried every tutorial available on internet, but nothing seems to be working. Pls help.

There is nothing special about hosting WordPress in a subdomain.

If you explain with a little bit of detail what you did, people might be able to find the missing piece.

I would start by checking simple things, for example, that yourhost.example.com resolves to the IP of your linode (use the host command for that), that the DNS subdomain you created is not so much recent that your PC still does not have it (you can add the IP manually to the "hosts" file in the meantime), that you can host a simple hello.txt in the root of your web, or that you can check that PHP is working by visiting a simple file.php containing this:

<?php phpinfo(); ?>

After this you could worry specifically about WordPress.