I don't know 'C', but usually a .hex files is what you burn to the chip, it's already complied. The .hex file can be much larger than the chips capacity, because it contains other information, that isn't sent to the chip. You post a link, of where you found this, maybe we can help from there.
**broken link removed**
found it! When you unpack it, rename the .Tar_02 file, to .tar, and you can extracted the contents...
Seems like all you have to do is burn the hex file, install the USB driver on your computer....