Internal hyperlinks are hyperlinks within a single presentation.
You might want to use these when some slides in your presentation refer to another one. Be aware that you can avoid setting internal hyperlinks because PowerPoint provide facilities to navigate within your presentation during your show . However, once you have got used to these facilities, you might find it quicker and more straightforward to set your own hyperlinks when your presentation has a great number of slides, or if these hyperlinks are requested by many slides in your presentation. In this example, we want to be able to return to the contents slide from any slide of the presentation. You might find this a good way to keep the hand in your presentation.