Creating a save system, starting by tackling var

I’m not very knowledgeable about coding yet, but I found another post by @Mert about the save system. I’m not sure if it’s quite what you’re looking for, but @eposic goes into great detail about the password system there.
https://forum.choiceofgames.com/t/about-save-system/652
The title is “About “Save” System”.