Within the media interface, you can upload PPT, PPTX or PDF files.  You can upload files by selecting "Media" then, "Select"

Please Note: Any PPT(X) of PDF file uploaded to the Media interface is converted to the "slides" format (a series of image files) by the TelemetryTV content server.

From the Playlist interface, once you add your slide as content, adjust the duration of slide/page rotation by specifying an amount of time in the "interval" field.  This duration sets the time each slide/page will run for before it moves onto the next page of content in that slide.