There are no saves. The game only uses the persistent file that Ren'py generates. If this file isn't being made for you, that means there's something wrong with your user folders somehow. Perhaps you don't have write access to your own user folder or there is already a Supermodel-folder in there that was created by another user (before a reinstall of Windows, for example).Also there are no saves. When I open the game I'm forced to start from the beginning every time.
There's not much I can do to help you with that since it's a Ren'py problem. You would have been unlikely to get saves working either. Just make sure that you know what to expect here. Supermodel saves automatically between chapters and matches. If you finish a chapter/match and exit the game, whatever you unlocked will still be unlocked. If this is not the case, you need to do some web searching for issues related to Ren'py and save folders.