Make player keep items through game instances?

I want my game to be divided into various places, with the posibility of the player traveling through them, now how can I make it so the player keeps the items in his backpack when teleporting through the different levels?

I thought that maybe by using the save instance mthod I could save the player's backpack but I'm not completly sure if it works that way. Should I use DataStores? How do I use it? or is there a better way to do it?