Your platform-specific account name or ID. The game's application or title ID. Every game has a unique ID. You should see files named save_.sav (Dead Island) and/or save_.sar (Riptide). Those are your saves, and there is one per character. There may be one extra (old) copy so make sure to pick the right one.
[US] Dead Island Riptide Starter Save. Description: Save details : Character: Sam B Modded Money, Godmode, Modded Stats, Modded Weapons, No zombie detection, TSMg9.