If you are one of the few people struggling with the datastore concept or just a beginner in general, I will share my understanding of datastore…
First of all, you have to enable API services: simply by going to game settings → security → Enable API Service and save
The next few codes are commented on so you can refer back to them when coding. It has also been designed so that you can edit three variables namely VERSION, and data_table which are self-explanatory in themselves:
-- PublicDS
-- handles all the data store that is seen publicly
-- aka all items in the leaderstats
-- services needed
local Players = game:GetService("Players")
local DataStoreService = game:GetService("DataStoreService")
-- constants variables
-- Changeable Values
-- change the version (will make a new datastore for each new version)
local VERSION = "v2"
-- add or remove elements from this table that you want to put into leaderstats
-- format: [dataName] = defaultValue
local data_table = {
["Money"] = 1000,
["Diamond"] = 50
}
-- handles leaderstats when player joins game
local LeaderstatsHandler_in = (function(player)
-- functions
-- get stats from the data store
local getStats = (function(statName)
local userId = Players:GetUserIdFromNameAsync(player.Name)
local temp = DataStoreService:GetDataStore(VERSION)
local success, currentStatValue = pcall(function()
local value = temp:GetAsync(userId..statName)
if value == nil then
return data_table[statName]
end
return value
end)
if success then
return currentStatValue
else
print("Error retrieving " .. statName)
end
end)
-- creates leaderstats folder to player
local leaderstats = Instance.new("Folder")
leaderstats.Name = "leaderstats"
leaderstats.Parent = player
-- sets the values under leaderstats folder
-- statName: string represents the name of the stat
local set_leaderstats = (function(statName)
local temp = Instance.new("IntValue")
temp.Name = statName
temp.Value = getStats(statName)
temp.Parent = leaderstats
end)
-- gets the values to set in leaderstats
-- by calling function set_leaderstats
for data, v in data_table do
set_leaderstats(data)
end
end)
-- Event when a player joined a game
Players.PlayerAdded:Connect(function(player)
print("Player " .. player.Name .. " has joined the game!")
LeaderstatsHandler_in(player) -- initiate the leaderstats for the player
end)
-- handles leaderstats when player want to save the datas
-- either by leaving the game or when server crashes
local LeaderstatsHandler_out = (function(player)
local leaderstats = player:WaitForChild("leaderstats")
-- functions
--set stats into the data store
local setStats = (function(statName)
local userId = Players:GetUserIdFromNameAsync(player.Name)
local temp = DataStoreService:GetDataStore(VERSION)
local value = leaderstats:WaitForChild(statName).Value
repeat
local success, errorMessage = pcall(function()
temp:SetAsync(userId..statName, value)
end)
until success
end)
-- saves the stats into data store by calling function setStats
for data, v in data_table do
setStats(data)
end
end)
-- to be called if and only if player is leaving the game or
-- when server crashed or closed
local save = (function(player)
LeaderstatsHandler_out(player)
end)
-- Event when a player left the game
Players.PlayerRemoving:Connect(function(player)
print("Player " .. player.Name .. " has left the game")
save(player)
end)
-- Event when server crashed or closed
game:BindToClose(function()
print("Server closed")
for _, player in ipairs(Players:GetPlayers()) do
save(player)
end
end)
Now you can create a currency, level but I will leave that to you however you want to implement it. 