Just copy the
QITools directory and its contents to the Mathematica base
directory or user base directory to install it system-wide or for a specific
user, respectively. You can find these directories by running
$UserBaseDirectory in a notebook.
The QITools package is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You can find the full license in the