Where do you put the remote probe for a thermostat in a tank?

I put the probe from my thermostats on top of the substrate on the warm side right Ive the heat source,you must remember if you put it to far from the heat source,the heat source will constantly heat up until the probe has achieved the temp you have set.So if its to far it will be to hot and to close it will be to cold,So just set it up like i said above and you should be good.The snake will not bother it ,none of my snakes bother the probe only some of my lizards.