The installation of GTPack follows the Mathematica standard. After downloading and unzipping GTPack, the content of the package has to be copied to the application folder of Mathematica within the respective base directory. Here, the user can choose between making the package available for all users of the computer or only for her- or himself. If the package should be available for all users, the corresponding folder to copy to can be found by opening a Mathematica notebook and typing $BaseDirectory. If the package should be available exclusively for the current user the respective base directory can be found by typing $UserBaseDirectory. According to the path of the base or user base directory (called $dir in the following), the folder containing GTPack needs to be copied to the directory $dir\Applications. Afterwards, the package and the documentation are available. The package itself can be loaded within a Mathematica notebook by evaluating Needs[”GroupTheory‘”].
Unfortunately, all add-ons and packages remain fairly hidden in the later versions of Mathematica. If you want to reach the GTPack guide page, open the Mathematica Documentation and scroll to the very bottom of the page. There you will find a link to “add-ons and packages”.
If you click the link you will get to a list of all packages which are located in $dir/Applications.
More information about GTPack can be found in our book. Check your institute/local library for a printed or an E-book version.