OP, meet ProfileService!
If you’re learning about DataStore, I heavily recommend you give this module a try, assuming that you’re trying to save individual players’ “have I done a quest or not?” related data. You can assign it via a table and have a player’s “Profile” save each time a change is made or when they leave.
It can seem a bit daunting at first, but it’s a godsend to your game’s DataStore workflow and efficiency.
We can’t really use these forums to give out individual scripts or guidance, but the documentation on there is easy to understand once you start demonstrating it yourself.
Have fun and good luck!