I can't view the link here from work for some reason, but essentially the hardest part is getting the old clutch quadrant pawl out. The stock plastic quad is two pieces: the big quad piece, itself, which looks a similar to the metal aftermarket piece, and the little upper baby quad thingy known as the pawl.
The quad assembly is on the accelerator pedal side, not directly above the clutch pedal where you'd expect it to be. Obviously, you first want to unhook the cable from the quadrant - pretty self-explanatory step, once you look at it. Then push off the hairpin clips with a screwdriver or pair of needlenose pliers (or your fingers, if you've got beefy fingertips), then first slip off the big quad piece. There will be an extra spring attached to it that will make a snap or BOI-OI-OI-OING! noise when you get it off - don't worry, you won't need it, and in fact you can pretty much just discard the spring and quad once you remove them. DO NOT throw away the hairpin clips, though, as you'll need those to hold the new quad on.
The upper pawl quad piece is a turd because 1. that spring attached to it is a bugger to slip off in order to make it let go of the little turd (usually a long flathead screwdriver works best for me on that), and 2. there's not enough room to the side to just slip the thing off the post it's mounted upon. Usually, you can pull down the carpet behind the pedals enough to be able to push the clutch pedal allllllllllll the way down as far as you can possibly get it, and then slip that pawl over the top of the big metal support piece that's in the way - you might also have to rotate the pawl upside-down to get it to slip over. Otherwise, you've gotta take a little saber-saw blade on a handle or somehow otherwise clip/snip/cut/saw the big round "ear" off that pawl to get it to flip over and slip off the end of the shaft it's mounted on. Again, it's hard to explain without any visual aid, but you'll see what I mean when you get under there.
A lot of guys insist you have to pull the front seat out completely to do it. I never have. I just slide it back as far as it'll go, and I'm all good. Then again, I'm kind of a skinny little runt.
Adjustible cables have a long threaded end and two nuts (uhhh-huh huh) on the clutch fork end of the cable - a large nut with a rounded end and a thinner jam nut to secure it in place. This is the end that tends to break on them. It's just a crappy design, plus the cable, itself, tends to be made a lot more flimsy than the Ford cables. Unless you can re-use your stock cable (you might be lucky and perhaps just the plastic quadrant has turned brittle and broken some teeth), I'd VERY strongly recommend getting a "universal" Ford OEM non-adjustible cable - Maximum Motorsports has them for around $75 shipped.
Hope this helps!