There's no error.
--TetherBLOX one = script.Parent.Part1 two = script.Parent.Part2 three = script.Parent.Part3 one.Visible = true ew = false go = true function new() mouse = game.Players.LocalPlayer:GetMouse() mouse.KeyDown:connect(function(keyPressed) if keyPressed == 'f' and go then go = false one.Visible = false two.Visible = true wait(1) ew = true if ew == true then two.Visible = false three.Visible = true wait(3) three.Visible = false end end end) end game.Players.PlayerAdded:connect(new)
If you are using a localscript you don't need to wait for a player to be added, the player is already added.
--TetherBLOX one = script.Parent.Part1 two = script.Parent.Part2 three = script.Parent.Part3 one.Visible = true ew = false go = true mouse = game.Players.LocalPlayer:GetMouse() mouse.KeyDown:connect(function(keyPressed) if keyPressed == 'f' and go then go = false one.Visible = false two.Visible = true wait(1) ew = true if ew == true then two.Visible = false three.Visible = true wait(3) three.Visible = false end end end)