Yea, what Phant said. Unzip the package. There should be a .bin inside. Also make sure you download the appropriate flash utility. Normally you can get that from the exact same site that you get the .bin file from.
Also one thing I learned that may make life easier is, if you have a Windows 95/ 98/ME CD, you can boot to dos with that CD so just the flash files in a folder on a FAT32 partition (you cant boot to a NTFS partition without a special boot disk).
Then all you need to do is press F8 at the boot screen and you will see a menu. Tell it to boot from the CDROM, and immediately press F8 again afterwards. Now you should get a menu with an option to boot to DOS. Then it might ask you if you want to boot to DOS with CDROM support or not. It doesn't really matter which unless the BIOS files are on the CD.
Then just run the bios utility (for example amfxx.exe binfile.bin)
The bios utility most of the time will tell you if the bin file is not the correct bin for your bios so it keeps you safe from flashing the incorrect one (although you can still make mistakes).
Good luck.