WordPress Theme is a skin (theme or template) for one of the most popular blogging software WordPress. A theme modifies the way the site is displayed, without modifying the underlying software. 

To add a new theme to your WordPress installation, follow these basic steps: 
1. Download the theme archive and extract the files. You need to preserve the directory structure in the archive when extracting these files. 
Using an FTP client to access your host web server, create a directory to contain your theme in the wp-content/themes directory provided by WordPress. For example, a theme named "th_theme" should be in wp-content/themes/th_theme. 

2. Upload the theme files to the new directory on your host server. 

3. To select the active theme for your site: 
Log in to the WordPress Administration Panel. 
Select the "Appearance->Themes" subpanel. 
Click on the preview for the theme you wish to activate.
At the top of the popup that appeared click "Activate WordPress Theme XXX".
To view the new look, click "View Site" at the top of the Panel's screen. 
Your selection should immediately become active.

