"make a clientsided floating arrow that floats above the player's next stage. Stages are in a folder called Checkpoints"

-- LocalScript in StarterPlayerScripts 
local Players = game:GetService("Players")
local player = Players.LocalPlayer
local character = player.Character or player.CharacterAdded:Wait()
local checkpointsFolder = game.Workspace.Checkpoints
local arrow = Instance.new("BillboardGui")
local arrowImage = Instance.new("ImageLabel")

arrowImage.Image = "rbxassetid://arrow_image_asset_id_here"
arrowImage.Size = UDim2.new(0, 50, 0, 50)
arrowImage.BackgroundTransparency = 1
arrowImage.Parent = arrow

arrow.Enabled = true
arrow.Size = UDim2.new(0, 50, 0, 50)
arrow.StudsOffset = Vector3.new(0, 3, 0)
arrow.Adornee = nil
arrow.Parent = character:WaitForChild("Head")

local currentStage = 1

local function updateArrow()
	local nextCheckpoint = checkpointsFolder:FindFirstChild("Stage" .. tostring(currentStage + 1))
	if nextCheckpoint then
		arrow.Adornee = nextCheckpoint
	else
		arrow.Enabled = false
	end
end

local function onCheckpointTouched(hit)
	local character = hit.Parent
	local humanoid = character:FindFirstChildWhichIsA("Humanoid")
	if humanoid and character == player.Character then
		if hit.Name == "Stage" .. tostring(currentStage) then
			currentStage = currentStage + 1
			updateArrow()
		end
	end
end

for _, checkpoint in ipairs(checkpointsFolder:GetChildren()) do
	if checkpoint:IsA("BasePart") then
		checkpoint.Touched:Connect(onCheckpointTouched)
	end
end

updateArrow()