WordPress is blogging software that you can install as an addition to your website. There are several different configurations you can use as far as the how people access your blog; you can use blog.domainname or domainname/blog or any other name you want to have people access the blog.
Adding a Word Press blog can be a very simple process.
1.     You need to be on a server that supports Word Press, such as one of the UNIX farm servers.
2.     You will need access to a MySQL database, normally this is set up on your account already.  If you do not have a MySQL database already on your account, you can email support@adhost.com and request access.
3.     Download the WordPress install files, this can be done by going to http://www.wordpress.org.  After you have downloaded the files, you will need to unzip them into a folder.
4.    Once the files are unzipped, open a file called wp-config-sample.php. You can open this file in a standard text file editor such as notepad or vi or pico.
5.     Save the file under a new name called wp-config.php. You will also need the information for your MySQL database.
6.    You are ready to input data for MySQL. This includes the DB name, DB username, DB Password, and DB server.  When you open the file you will need to look for the following area
// ** MySQL settings - You can get this info from your web host ** //
/** The name of the database for WordPress */
define(’DB_NAME’, ‘putyourdbnamehere’);
/** MySQL database username */
define(’DB_USER’, ‘usernamehere’);
/** MySQL database password */
define(’DB_PASSWORD’, ‘yourpasswordhere’);
/** MySQL hostname */
define(’DB_HOST’, ‘localhost’);
7.     Upload all of the files to the server via FTP connection into the folder you want to use to access WordPress.
8.    Once uploaded, you can run the install file which would be http://mydomain.com/wp-admin/install.php. You will do this by going to the file via a web browser.
9.    Once you run this file, it will ask you for the blog title and your email address.
10.    You can now log in with the username “admin” and a password that is randomly created. This information will also be emailed to the address you provided.
11.    You should change the password by going to the Profile for the Admin user and looking for “Change Password.”
12.     You can then start to customize the settings for your blog from the Admin page.
13.    Further help for Word Press can be found by going to http://codex.wordpress.org/Installing_WordPress#Famous_5-Minute_Install