I need help with my sister's game for pulp

So I have a game my sister made I was trying to help her with a saveing system I Inserted he code I got from a source on youtube I trust as a game but now it wont let me undo it dose anyone know how to help. Side note an old veshion of the game is on our playdate if that helps.

If you have the old version on your computer there should be a file inside the pdx folder called data.json. If you unzip it you can import it into Pulp to go back to that version of the game. Be careful because anything you import will overwrite your current project!

In the future a good habit is to save backups of your game by clicking "export". If you keep several backups (give them different names) you can then use "import" to go back to an old version.

Good luck with the game and have fun!

thank you this helped a lot.