Iris Documentation (free version)
Installing Iris (free version)
To install this theme you must possess a functioning version of WordPress already installed. For information about installing WordPress, please see the WordPress Codex - http://codex.wordpress.org/Installing_WordPress
Upload via FTP:
First, unzip the zip archive you have downloaded. Search the folder named Iris-Free.zip. Open this archive and upload Iris folder to your server via FTP into the directory /themes/ of your WordPress installation (wp-content > themes).
Upload via WordPress admin:
Go to your WordPress admin, and in the menu entry Appearance > Themes > Add New. Upload the file Iris-Free.zip.
Installing WordPress http://codex.wordpress.org/Installing_WordPress