Walk-Up Dining Waitlist Question

[Abbey1]

Hi all! I'll be visiting in a few weeks and am wondering about how joining a dining waitlist works on the app. I've never done this before (visiting for the first time since January '20 - was this a thing back then?). I wasn't able to snag an Oga's reservation, so would my best bet be to join the waitlist as soon as we enter the park? I'll have a group of 5. Thanks!