I'm currently making an adventure map and I want to know how to trigger Command Blocks when a player walks through a certain area. For example, if a player walks through a certain part of a cave, it would say "Don't go down there", or something. Or it could trigger a jump scare (but that's not what I'm looking for).
Specifically, I'm making it so that when the player walks through an area, it says "I think it would be a good idea to go exploring." in a first person perspective.