I was wondering if the DataStores for player’s Level and XP carry over by default or if I have to do something to make them carry over.
You might want to use the Roblox wiki search function before posting.
Data stores are shared per game , so any place in a game, including places in different servers, can access and change the same data.
To answer your question, yes. If places are in the same universe then simply retrieve data using the same string data store name on the other place, say you have 50 coins, you save it to your data store using SetAsync() or UpdateAsync(), if you teleported to the other place under that game(same universe, like you have it set up) simply use GetAsync() like you were getting the data from the original place, make sure the data store string name is the same.
Best of luck.
yes
The wiki has some good examples: Data Stores | Documentation - Roblox Creator Hub
If you don’t understand something, don’t be afraid to ask.
If a player is changed (like a insert of a model). Does that carry over?