After downloading the .rar file below make sure that you follow the instructions on how to install the tool by looking at the first video '1. Preface And Install'
found on the previous/main page for this tool, so to avoid unnecessary problems during install.
To update to a newer version of the tool you simply just download the tool like normal and overwrite all the files on your drive tool location with the updated ones in the .rar file. After that when restarting the tool in Maya a popup should flash informing you that the tool has performed an update.