They went back into Popplet and added additional (red) boxes to make notes of things they would need for the filming: location notes; props and who was responsible for them; costume notes; and so on
They filmed everything hand-held using the iPad. With the big screen it's easy to see what's happening. The iPad is quite easy to hold steady and quite easy to do camera moves like panning and so on.
Check The Shot
The iPad made it easy for them to review each take so they could tell when they had what they needed.
After each scene, they did a rough edit of the shots they had using iMovie. When those shots didn't cut together, they simply thought about what they might need and just went back and shot it. When each scene was completed, they went back into Popplet and made the border of that scene green to show that it was done.
The first scene they shot didn't work. No matter how they tried to edit it, the shots didn't go together. So they redid one shot and edited it in. And it worked!
They went on in this way until they had a finished film.