How would a proximity-based dialogue system work?

Just as the title states, I'm currently interested in creating a proximity-based dialoguer system so that whenever the Player approaches a certain object then a StarterGui could be prompt, reading off text. Of course a "next" button would be handy too, This is not a request but I'd very much appreciate a nudge to the right direction, I'm pretty new to scripting so please forgive my lack of knowledge.