How to make an enemy chase you and catch you when close (like slendytubbies)

Hi there, I am still working on the horror game, but I asked how to make an enemy appear and disappear, yet I got the script but it was saying a game object was not in on the enemy, so now, I am asking if there is a way to make the enemy chase the player and when he is in a close distance, catch the player. I am really disperate now. Something like slendytubbies, but if you can help with a popup script, that would be fine. Oh yes and if possible to add audio when you see it. Please and thank you.