How do you have a gui's propertys save with datastore?

So i'm trying to make a find the game like find the chomiks or find the slenders ect and when you touch one of them I used a simple notification script that appears in the bottom right of the screen but they aren't like badges so I need to make an index so you know which ones are already found the problem is if you leave and rejoin it will say you didn't find the ones you already found. So I'm wondering how you could go about saving something like that with datastore any help is appreciated.