For my Gen 5, I just looked in this book at wal mart and found the sizes for my blades and bought Rain-X blades. The directions were on the back and it took awhile to figure out but i got it in the end.
When you try to take them off you can kinda figure out how to do it. You take off the wiper blade by holding down this clip and then sliding it off and you're left with a hook. With the hook you hook it onto the new wiper blade and it snaps on.
Not much of a good description but that's how i got it
-Custom 2.5in Cat-back Exhaust + Borla Muffler + Weapon R Dragon Intake + TRD Rear Sway Bar + TRD Springs + TRD Front Strut Brace