If you are seeing question marks or strange symbols when you open the font to install it, this means you are trying to install the WebFonts we have provided, which are for Web/HTML use only (stated on buying options tab).
WebFonts cannot be used in desktop environments and or applications, as well they will not work correctly or even install. These details and more are covered in our WebFont license.
If you need your font for both web (html) and desktop (e.g. Adobe, Microsoft applications) use, you will need to purchase both the WebFont and Desktop formats.