How do you make a Mc follow

Hi everybody i just want to know how do you make a movie clip follow another movie clip and also face the direction. it would be great 2 know thanks.

P.s did i say thanks

oh another P.s
i also want to know if i can have it stop following a certain distance away from the mc and then go to a different frame(like a enemy stops moving a certain distance then it will shoot him or something) then move again once the other Mc moves