Interval or timer?

Hi All,
I’m building a quick series of slides but there are a couple I know people aren’t going to look at long enough to gain any insight. For legal reasons I need to do due dillegence and make sure people at least stay on it for several seconds.

My idea is to set up the next button so that if they click it after only being on the page for (arbitrary number) five seconds or less it would pop up a text asking if they took enough time to read it and explaining why it’s important to read the page completly. If they click on it after they’ve been there for more than the five seconds they would be allowed to move forward.

I know how to do the if/else, popups etc but what I’m not sure about is what to use for the timer portion. I know there are several ways to do it using intervals, mytimer, etc but I am not sure which is the best route. Can someone point me in the right direction?