To install symfony following are the list of required requirement:
- The minimum version of PHP should be 5.5.9
- Need to enable JSON
- Need to enable ctype
- Your php.ini should have the date.timezone setting

Run the following command:

# composer create-project symfony/framework-standard-edition symfony_dev "2.8.*"

( symfony_dev is directory name and 2.8.* is the version which need to install)

Run server if default installation:

# php app/console server:run

Following is the url for default installation
Ex. http://127.0.0.1:8000

OR Create virtualhost as follows: Run the command and add the entry as follows

# sudo nano /etc/apache2/sites-available/000-default.conf

<VirtualHost *:80>
    ServerName xyzsymfony.com
    DocumentRoot /var/www/html/symfony_dev/web
</VirtualHost>

# sudo nano /etc/hosts

127.0.0.1 xyzsymfony.com

Now the url after create virtualhost
Ex. http://xyzsymfony.com