To install a WordPress Theme you must have a working version of WordPress already installed. For information regarding installation of the WordPress platform, please see the WordPress Codex.
1. Login to your WordPress Dashboard and go to Appearance → Themes. Click “Add New“.
2. On the “Add Themes” screen, click “Upload Theme”.
3. Choose the theme zip file you downloaded from NiceThemes and click the “Install Now” button.
4. Activate your Theme by clicking the “Activate” link.
That’s all you need to do to install your WordPress theme. Some themes need some shifting around of the Widgets and Page Templates.
If you are installing your theme via an FTP Client, please make sure that the path is wp-content/themes/themename/ and not wp-content/themes/themename/themename, this will affect the ajax and commenting of your theme