This is my first time using data stores an i need a bit of help?

Every time I try to save the data it says the error message and UserId is not a valid member of RBLXScriptSignal and when I try to save it when leaving it says ServerScriptService.Data Stores:28: attempt to index number with 'Value'

player = game.Players.PlayerAdded
local DataStoreService = game:GetService("DataStoreService")

local GravelColor = DataStoreService:GetDataStore("GravelColor")

local ColorOfG = game.ReplicatedStorage.Color

game.Players.PlayerAdded:Connect(function(player)

    local data
    local success, errorMesage = pcall(function()
        data = GravelColor:GetAsync(player.UserId.."-color")
    end)

    if success then
        GravelColor = data
        ColorOfG = GravelColor
    else
        print("There was an error when getting your Data")
        warn(errorMesage)
    end

end)

game.Players.PlayerRemoving:Connect(function(player)

    local success, errorMesage = pcall(function()
        GravelColor:SetAsync(player.UserId.."-color", ColorOfG.Value)
    end)

    if success then
        print("Player Data Succesfully Saved")
    else
        print("There was an error when saving Data")
        warn(errorMesage)
    end
end)

while true do
    wait(20)
    local success, errorMesage = pcall(function()
        GravelColor:SetAsync(player.UserId.."-color", ColorOfG.Value)
    end)

    if success then
        print("Player Data Succesfully Saved")
    else
        print("There was an error when saving Data")
        warn(errorMesage)
    end
end

Sorry if this is really obvious or something this is my first time using data stores