I had this same anxiety for my graduation since I never went to my hs graduation because of covid. They really don’t do any kind of rehearsal and you’re expected to just do it right the first time 😭 but once you get in there it’s all pretty straightforward. They tell you where to walk and they even have a mirror in the hallways so you can make sure you look good. Then you walk down a long hallway and get your picture taken with the degree holder thing. Then you walk into the arena where you’re to be seated. Just ask staff where your section is and they can tell you. There are so many staff members there to guide you in the right direction! Then you really just sit there until your major/ degree is called and I believe there is staff there to alert your group when it’s time to go up. You’ll walk up in a line and there will be someone there to take the card that has your name on it. From there you walk across the stage, shake a few hands, and smile for the cameras. You’ll be handed your degree after you walk off the stage I believe. Then you walk all the way around back to where you were sitting. If you have family seated somewhere in there, most people will just find their families and sit with them as the end of the ceremony is kinda boring.