If you're talking about the presentation product made by Apple, here's what to do:
- Select the object you want to create a hyperlink for.
- Open Inspector (View > Show Inspector).
- Open the hyperlink tab and check the box that says 'Enable as a hyperlink'.
- There are five options to direct the hyperlink to a specific object.
- Slide: Directs the hyperlink to one of the slides in your presentation.
- Webpage: Directs the hyperlink to a webpage.
- Keynote slideshow: Makes the hyperlink open another presentation on your computer.
- Email message: Makes the hyperlink open an email message.
- Stop slideshow: Stops the slideshow when the hyperlink is clicked on.