Pop up each time someone comes to the site - same day.

Hi! I see all the options in the pop-up pro settings but I'm just not seeing this one thing. I'd only like users to see the pop-up once - but PER site visit. So if they come to the website - see the pop-up and then navigate away from the website (close the window or tab) and come back in the afternoon - it comes up again. How do I do that without them seeing it on EVERY page. I want them to see it ONCE per site visit. THANK YOU!