Assuming that you want unlimited Savegames (like Skyrim, Witcher 3).
I would make a MainSaveGame that contains a StructArray with all the Info you need (SaveGameName, Date, Time, Thumbnail etc.).
Make a Widget that creates Buttons for every Index of the array.
Every time you create a new Save it gets the last Index and creates a new one.
Havent done that before but I think that should work.