Hi Paul,
Basically the snare is a noose of wire or light line that is strategically located in a small animal pathway in the woods, the noose is normally slightly larger than the anticipated dinners head. The animal runs down the pathway, it's head passes through the noose and the animal is strangled. When approaching a snared animal, use caution, it may still be alive and if so, will rightly be ready to use teeth and claws to good effect. Keep in mind that this is normally used in a life or death matter for getting a meal to survive. It is not a normal sporting type method of hunting, and in some places may be illegal and/or have restrictions regarding the use of snares.
While one can be used, having several set at a time will help ensure a meal. Be sure to remove the snares when moving on though...
Do a forum search, select all dates, all posts. Key in searchwords, "cheatsheet" "snare" "stop list". There were several fairly extensive threads over the last year and a half that discussed snares. The "cheatsheet" is a little list that Bill Vannerson set up and kindly shared among ETS readers as well as on his scouting website (sorry, forget the name of it at the moment, I'll look for it later). It is a several page folding list that prints out in a size that nicely fits into an Altoids tin. I believe that he had two cheatsheets, one with and one without the snare info.
Also see about downloading the armed forces survival manual. It is in *.pdf format and has all sorts of great info. regarding food procurement etc. I'm going to look around and see if I can find the actual link names to make it easier for you. Seems to me that Doug has a link to the survival manual somewhere on ETS. HTH
Comanche7