Enter Trigger zone, press key, play audio one time... How?

I want to enter a empty game object that has a box collider and when i’m in it and press a f it plays a sound, yet if im out of it it wont when i press f. how can i arrange this and what script should i use?

Set the box collider on the empty game object to Is Trigger in editor.
Pseudocode:

OnTriggerStay() { 
if (input.F) play.sound
}

Note the specifics of using OnTriggerStay