Lock-rite is insanely easy...
First pull your cover, bottom end first, to drain the oil out. The completely remove the cover. This will expose the ring gear/carrier and caps. take time to make the main caps and carrier in relation to it. Make sure you have a haynes or a chiltons for torque specs. If your axle is a c-clip style which I'm pretty sure the AMC 20 is. There is a small bolt on one side of the carrier, remove that and the post that it's connected to. Your going to need to push the axleshaft in to remove the c-clips. once the c-clips are removed pull the axleshafts out enough to clear the carrier.
This is the main part to pay attention too....
Remove the carrier main caps, making sure that you keep the bolts/caps together.
Pull the carrier and shims out. take not of how many shims are on either side. if you don't you'll be getting towed to CT axle to get the carrier shims set back up. once the carrier is out, remove the spider gears as these will be replaced by the locker.
In your lock rite kit, you should have 4 clutch plates, 4 springs, 4 dowels, and two side bearing. Two of the clutch plates are different than the other two, aka two are flat and two fit into the inside of the carrier. the ones that fit inside the carrier, put them in either side with the side bearings between the clutch plate and the carrier. Take the dowels and insert them into the other two clutches there are shallow holes and deep holes. (they go into the deep holes), you'll notice the teeth are going to be pointed away from the center. Remember that post that you pulled out... well that's going to be reinstalled between the inner clutches, so you have to mind how the inner clutches line up.
ok with that being said... once the dowels are in place, position the inner clutches into the carrier. This is where it gets frustrating!!! the springs have to go into the holes to force the dowels out. Here's what I did, I took the post and reinserted it for the time being, just to get the springs in. before you put the post in, push the dowels from one clutch into the other. just to hold the two together. once you have the post in, take a small screw driver and push the springs into the openings. do it in like an "X" formation. once you get all of the springs in, remove the post and line the inner clutches up to put the post all the way through the carrier. and put the carrier back in with the shims on their appropriate sides. reinstall the carrier main caps, and torque. now for the fun part. The clips now need to go back in. push the axle shaft in on one side and slide in the c-clip, you might have to turn the axle shaft a little to get it in. now do it on the other side. once the c-clips are in, the post can now be reinstalled. get the post reinstalled and your done! just rtv the cover and put gear oil in and that is that.