Right at 7am, click Join, Join, Join (at least this is what it was on my iphone 11). Don't stop to read anything else on the screen, just click Join on each new screen as fast as you can.
Make sure you don't have any notifications set up on your phone that send you a reminder at 7am. I have an app on my phone that sends me a reminder at 7am everyday that I forgot to turn off. Thank-goodness my DH was able to get our BG's that day!
When I say right at 7am, I really mean right at 7am. The second your phone clock turns to 7am. Not 10 - 15 seconds later. By that time, you are too late.
Before your HS day, make sure everyone in your party has a ticket and a park reservation for HS and they are linked in
MDE. This way, when you go to join, the system should automatically select everyone in your party.
Good luck!!