See also installation instructions in the ReadMe page.
The video tutorial below shows how to install the GCD software. It's important to install the GCD software using the Windows user account under which the software ArcMap and GCD will be run. You might be asked for administrator privileges during the installation and this is OK. Do not run the GCD install process as the Administrator if you intend to run the software under a different user account.
Also, make sure that you choose the "Just Me" option during the install and not the "Everyone" option. This will ensure that the install process copies the necessary files to your user profile folder.
If you intend to uninstall ArcGIS, you must uninstall the GCD software first. Failing to do so will orphan the GCD software, leaving it impossible to uninstall.