Starting a presentation
Click the three dots at the top right of any Confluence page. The menu contains a “Present” option:
In the dialog that pops up, choose a theme (design template) and then start the presentation:
There’s another way:
Start Buttons
In some scenarios, your users shouldn’t be bothered with menus and dialogs. Presenter offers a Start Button macro for these cases. It looks like this on your Confluence pages: