Download the ATD Events app from iTunes or Google Play. If you have created a schedule on the schedule planner page (be sure to log in), you can download your schedule to the app with the same login.
Please note that download is only one way, from the website schedule to the app. Once you make changes to your schedule on the app, they will not be transferred back to your online planner. For the best experience, use the online planner until you are ready for the conference, then use only the app. Moving back and forth between the two platforms will not sync all changes.