If you want to create a well structured demo or tutorial it's best to create a script first so you can layout exactly what you want to say. To help make this process easier you can create a Scripted Recording. In a Scripted Recording you first enter the text for your script and then record the audio. Once you have the audio recorded you can record the corresponding screen video using a special version of the recorder which plays back the audio in your script while you follow along. When you have the audio and video completed you can publish your video and the app will generate captions using the text from your script.