Okay, I’m gonna help ya. I would suggest an investigation check 'cause you know what you’re looking for. Like, you’ve seen some kind of door or something but don’t know what’s happening. So you’re trying to investigate where it is.
Also, HINT. If you need explanations at all, you can always go to your character sheet and click on the words, like “investigation”. Then it’ll come up with a box in screen-right telling you about it.