If you secured a spot for the Guardians of the Galaxy: Cosmic Rewind Passholder Previews, check your plans in your My Disney Experience account. A Disney Park Pass reservation for your date should be there by now.
Disney is also sending out email reminders. If you haven’t received one yet, don’t panic, it will come closer to your date. Keep that email as new and print it if you can, because you will need to show it in order to ride.
When your date arrives, show up a little bit early to the ride area. Everyone in your group should arrive together. Have your email handy, as well as your photo IDs. It probably isn’t a bad idea to have your Annual Pass out and ready to show. Cast Members will check your confirmation number and scan your MagicBand when it’s your turn.
One quick word of warning about Guardians of the Galaxy: Cosmic Rewind. I know several people who have had slight problems with motion sickness after riding. It hasn’t been Mission: SPACE bad, but some were still not expecting an issue. This hasn’t stopped them from wanting to ride again. If motion sickness is sometimes an issue for you, plan to sit down for a few minutes after you ride. You might also want to take Dramamine before.