*** Installing WordPress Themes
-------------------------------
1. Access your Web server using an FTP client or Web server administration tools.

2. Unzip the downloaded theme zip file.

3. Copy or upload the entire theme folder to the /wp-content\themes\ folder in your Wordpress installation.

4. Login to your WordPress administration panel and select Design -> Themes.

5. In the 'Available Themes' section click on your theme title or screenshot, then click the 'Activate Theme' link to activate it.

For more information please refer to the official WordPress documentation:
http://codex.wordpress.org/Using_Themes#Adding_New_Themes