how to install tacomethrus in Cavalier 96 2.4L

Hi, I have a Chevy Cavalier from the 1996 engine 2.4 and by factory it does not come with Tacometro, the thing I want now I want to install a tacometer but I do not know where to get the signal for the tacometer if someone can help me ???? since what is heard for is that the signal can be taken for the crankshaft but where it is located or what is ... from before hands thank you very much