If you're a Haiku Deck Pro subscriber, you can add audio and export it to video using our Haiku Deck Presentation Video feature. Learn more about it here.
This will work for most users most of the time, but if you're looking for an alternative way to create and edit a presentation video, you'll need to export your deck to PowerPoint / Keynote with the steps in this article.
If you have Keynote on a Mac, you'll want to open the PowerPoint file in Keynote on your Mac. From there, you can go to File - Export, and choose to export a Quicktime movie of your deck. Before exporting, you can even add narration and audio to your slides, or use any of Keynote's other features. For more help with Keynote, you can click "Help" on the menu bar and choose Video Tutorials or Keynote Help.
If you'd rather add your audio from iMovie, you can export a Quicktime movie or Images from Keynote and drag and drop the exported files into iMovie. The narration tool in iMovie is easy to use as well and can be broken up into multiple takes more easily than it can in Keynote.
If you're on a PC, you can follow the steps above, but instead of opening the file in Keynote, you can open it in PowerPoint. From there, you can go to File - Save As, and under the file type, choose to save your presentation as JPG files. This will export a series of images you can use in a program like Windows Movie Maker to create a video.
We're working on creating a resource about this topic specifically, so if you have any other questions or suggestions, feel free to let us know. We'll update this article when we have more on the topic!