Just put the pictures you wish to present on your Confluence page
Just click at the picture you like to start the presentation.
By using < and > you can slide between your pictures
click on the presentation button, to start a presentation
Now you in the presentation Mode, by using your arrow Keys to can slide to the next picture
Look at all the Pictures that involve your presentation by going to the left down side, there you are able to choose directly the picture you maybe have to use