Getting a boarding group isn't quite the final piece of the puzzle. You still need to show up at the attraction when it's your time to ride. The easiest way to do that is to turn on push notifications for the Disney app.
When your boarding group is called, you'll receive a push notification letting you know it's time to ride. You have an hour to make your way to the attraction before the window closes. They may be a tad lenient under extenuating circumstances, but do your best to get there on time. You can use the Disney app to check your estimated return time and how many groups are in front of you throughout the day. Good luck, and have fun!