How to install:
Put the attached file in the xlstart folder which will load it when you start Excel. The folder location is different for each version of Excel, but is generally somewhere under:
C:\Program Files (x86)\Microsoft Office\ [version] \xlstart
alternatively:
boot Excel and choose [ File -> Options -> Add-ins -> Go ] to manage Excel add-ins, then browse to the file you downloaded from here. People have had problems having it load each time when using the add-in UI, the xlstart folder seems more reliable.