Granted, public speaking is a little different to novel writing and filmmaking. For a start, you typically have a lot less time to share your story! But you can still model it on the Hero’s Journey to ensure that it has the key elements and a gripping narrative.
The Hero’s Journey is not the only story model you should ever use. But it’s certainly a good one, tried and tested. So use it as a reference point. Take the story you want to share and see how well it fits.