If you want to view a slideshow of your photos in a certain sequence - use the [ My media files ] tab of the Endless Slideshow Screensaver settings. This tab allows you to create a fixed list of photos and view those photos in a slideshow in the exact order they appear in this list. This tab is also useful if you don't want the software to re-scan the folders looking for the files every time the slideshow is started. For example, when new photos are rarely added.
So, if this is the case, open the Endless Slideshow Screensaver settings, select the [ My media files ] tab and check the [ Add media files from this list to the slideshow ] box.
Now you can use the [ Add all media from a folder ] button to choose a folder and add all media files from that folder automatically. Or use the [ Add media files ] button to choose individual files to be added to the list. Both these buttons have drop-down menus that allow you to decide where to add new files: to the top or bottom of the list, before or after a file that is currently selected in the list, or at random positions:
You can sort all files that are currently added to the list using the [ Sort media files by ] button. It has a drop-down menu with all available sort options: