Lance,
Yep, that's pretty much it. You can make a solid loop on the other end of the cable to use in securing the snare to a fence post, etc. Just feed the snare through the fixed loop in the end to form a "lasso" to slip around a post, tree, or whatever.
When you drill the slide-hole in the washer, use a drill bit that's just slightly larger than the cable (I.E. 1/16th inch cable, and a 3/32 inch drill bit).
The critters don't slip out.
Oh, and you can put one of those "barrels" shown in the picture of the snare in a position to keep the loop from getting small enough to catch a deer's leg, dog's leg, etc. Since it won't get small enough to lock on the leg, the leg slips out. You prevent catching larger animals by using that, and setting the snares at rabbit level, rather than high enough to catch the head of the larger critters.
Snares can be made and set to target very specific animals; you just need to be sure to use certain precautions to keep from catching something that can get you into trouble.
Oh, and congrat's on catching the jackrabbit.
Daryl