DataStores allow you to keep data between servers.
It is used usually for player data.
Every datastores has keys, these keys have data in them, so the key can be someone’s userId, and the data is the player’s data.
To get a DataStore you do DataStoreService:GetDataStore("DataStoreName, hello!")
You have some calls, but for people starting out, I recommend looking into :SetAsync() and :GetAsync()
SetAsync will SAVE/SET data to a key.
Example:
DataStore:SetAsync(player.UserId, data)
GetAsync will get data from a datastore. Example:
local data = DataStore:GetAsync(player.UserId)
One thing is that datastore calls can fail. So you should use pcall on these requests.