The downloadable files are stored in Stuffit (.sit) format. Download Anypia.sit and expand the calculator using Stuffit Expander. This creates a folder named Benefit Calculator. It contains 32 files and 2 subfolders:
Start the calculator by double-clicking on Anypia. A desktop alias can be created for Anypia using the usual facilities available in the MacOS. Start your browsing of the help files with main_index.html in the html subfolder.
To uninstall the calculator, drag the Benefit Calculator folder to the trashcan.