Select the Presentations tab
Select presentations loops from the toolbar
Select the Plus icon
Give the presentation loop a name and select save
Drag and Drop the presentations that are to be included in the loop onto the page
On each thumbnail select the time button at the bottom right and select a time the presentation loop plays on the screen
Add the time on each presentation and select save
Select Screens then presentation loops from the dashboard
Drag the presentation loop to the screen(s), the thumbnail will now contain a presentation loop icon at the bottom left