Option A: (fastest) Using video recording on a smartphone (or other camera), record frames from your storyboards while you provide the sound to create something similar to a story reel.
Option B: (advanced)
If you want to go to the next level, try using a video editing app for your phone. Take photo of each storyboard and arrange them in a sequence. A few free and highly rated apps are iMovie for iOS, and Power Director for Android.
Option C: (advanced) If you’d rather work on computer, search for video editing applications that import video, photos and audio files and allow you to arrange them in a sequence.
Part D: Share your work! Upload exported story reels to youtube or Vimeo and add the hashtag #pixarinabox