Powerpoint files are not a photo format so you cannot send the ppt, pptx files directly to the frame. You can either export Powerpoint to Photos, or convert it to a video. Search via Google "export powerpoint to image" and there will be multiple results of how to do this.
Make sure to save the names of each photo with photo001, photo002, photo003....photo999
If you don't do this then you won't be able to order the photos correctly.
Next load the photos to the frame. Go to my.photospring.com
Send the photos into an album by giving the photos a title when you send them.
Select the album to display on your frame.
Finally use alpha sorting for the playlist.
Tags: alphabetical sorting, slides