There has been a lot of talk ever since Rise of the Resistance opened about how you need to arrive at the park hours early in order to get into a Boarding Group. If you want to be in a guaranteed group, you still need to be in Disney’s Hollywood Studios when it opens. If you’re willing to take a chance, you might be able to wait a little bit longer. The past few days I’ve noticed that spots in Backup Groups are still available two to three hours after the park opened to the public. A Backup Group does not guarantee that you’ll ride, but they have been going through the groups quickly lately and the Force has been with most of those in the higher number groups.