1. Create your project folder at path var/www/html

    cd /var/www/html

      mkdir magentodemo                // create project folder if you have not created any folder yet

2.Create a virtual host for your Magento store

    sudo nano /etc/nginx/sites-available/magentodemo.com

3. Add the below configuration in the host file

    upstream fastcgi_backend {

    server unix:/run/php/php7.1-fpm.sock;

   }

   server {

      error_log /var/log/nginx/magentodemo-error.log;

      listen 80;

      server_name localhost.magentodemo.com;

      set $MAGE_ROOT /var/www/html/magentodemo;

      include /var/www/html/magentodemo/nginx.conf.sample;

  }

Replace magentodemo.com with your domain name

4. Activate the newly created virtual host by creating a symlink to the /etc/nginx/sites-enabled directory

    ln -s /etc/nginx/sites-available/magentodemo.com /etc/nginx/sites-enabled/

5. Test the configuration

     nginx -t

6. Create an entry in your host file

     sudo nano /etc/hosts

     An entry like below in host file

    127.0.0.1 localhost.magentodemo.com

7. Hit the url on your browser

    http://localhost.magentodemo.com

It Should work !!