how da hell do i make a model know if a player is near it and go to him?

im working on a fnaf fangame in roblox and i have a model of my animatronic (withered bonnie), i made it walk on a set path but i also would like for if the player is near it by like 50 studs to chase him, but i just cant seem to find any tutorial on smt similar.

if anyone knows how i would do that then please help me