Trigger zone (help)

Hello everyone. I have one question. I can’t write a one code. I want make an entity,which turns on,if player stop in trigger zone of this entity. How i can do that thing?

Not exactly sure what you mean but this might get you started

Sorry for my bad english speech.

I make entity addon for gmod,not map. Okay, I’ll try to explain better. I wanna make an object that will be handing out ammunition from a distance.