hooking up tach to 25ESH

I have a 2007 25ESH.(25hp, 2 stroke, tiller handle w/electric start, no ignition switch) I have purchased a Teleflex tachometer, and am having a hard time finding any tech support for how to connect it. The place where I bought the tach and the place where I bought the motor seem to have no idea how to make it work. Any suggestions would be greatly appreciated.