Config Apache 2.4 in Ubuntu

From Ubuntu 12.04 LTS, Apche have new version 2.4 which is different from 2.2 and below.
The configuration hierarchy is listed in apache2.conf file 's comment.

# /etc/apache2/
# |-- apache2.conf
# | `--  ports.conf
# |-- mods-enabled
# | |-- *.load
# | `-- *.conf
# |-- conf-enabled
# | `-- *.conf
#  `-- sites-enabled
#   `-- *.conf

# * apache2.conf is the main configuration file (this file). It puts the pieces
#   together by including all remaining configuration files when starting up the
#   web server.
#
# * ports.conf is always included from the main configuration file. It is
#   supposed to determine listening ports for incoming connections which can be
#   customized anytime.
#
# * Configuration files in the mods-enabled/, conf-enabled/ and sites-enabled/
#   directories contain particular configuration snippets which manage modules,
#   global configuration fragments, or virtual host configurations,
#   respectively.
#
#   They are activated by symlinking available configuration files from their
#   respective *-available/ counterparts. These should be managed by 127.using our
#   helpers a2enmod/a2dismod, a2ensite/a2dissite and a2enconf/a2disconf. See
#   their respective man pages for detailed information.
#
# * The binary is called apache2. Due to the use of environment variables, in
#   the default configuration, apache2 needs to be started/stopped with
#   /etc/init.d/apache2 or apache2ctl. Calling /usr/bin/apache2 directly will not
#   work with the default configuration.

I. How to change DocumentRoot in Apache 2.4

 I found that we need 3 steps:

1. Add more Directory  in  /etc/apache2/apache2.conf

<Directory YOUR_FOLDER>
 Options Indexes FollowSymLinks
 AllowOverride None
 Require all granted
</Directory>

2. Change default documentRoot in /etc/apache2/sites-available/000-default.conf :
   DocumentRoot /var/www

to

  DocumentRoot YOUR_FOLDER

3. Restart your Apache server : sudo service apache2 restart or  sudo /etc/init.d/apache2 restart

II. How to add virtualhost

We need 3 steps to complete this configure

 1. In /etc/apache2/sites-available folder  create SITENAME.conf file
( SITENAME is your name you want to set)
In SITENAME.conf  config your new virtual host

<VirtualHost *:80>
        DocumentRoot  YOUR_NEW_VIRTUAL_HOST_FOLDER
        ServerName YOUR_VIRTUAL_DOMAIN_NAME
        ServerAlias  YOUR_VIRTUAL_DOMAIN_ALIAS
        ServerAdmin webmaster@localhost

        ErrorLog ${APACHE_LOG_DIR}/error.log

        CustomLog ${APACHE_LOG_DIR}/access.log combinedme

</VirtualHost>

You can see more how to config in this link