Why is this command not working? Can someone help me solve this? This is a countdown command.

This is in a local script:

game.Players.LocalPlayer.Chatted:connect(function(msg)
	local player = game.Players.LocalPlayer
	local rank = :GetRankInGroup(2714283)
	if rank >= 1 then	

if msg == ":Countdown" or msg == ":countdown" or msg == ":cd" or msg == "CD" then
for i = 5,0,-1 do
	wait(1)
	script.Parent.Text = "Countdown: "..i
	if script.Parent.Text == "Countdown: 0" then
		script.Parent.Text = "Times Up!"
		wait(5)
		script.Parent:Destroy()
	end
end

This is in StarterGUI. Followed with a ScreenGUI. Then a textlabel. Then a LocalScript.

You forgot an end after your function. lots of ends, sorry.

game.Players.LocalPlayer.Chatted:connect(function(msg)
    local player = game.Players.LocalPlayer
    local rank = player:GetRankInGroup(2714283)
    if rank >= 1 then   
--if msg == ":Countdown" or msg == ":countdown" or msg == ":cd" or msg == "CD" then
	for i = 5,0,-1 do
    	wait(1)
    	script.Parent.Text = "Countdown: "..i
    	if script.Parent.Text == "Countdown: 0" then
        	script.Parent.Text = "Times Up!"
       		wait(5)
        	script.Parent:Destroy()
    	end
    end
    end
end

It's not the best but it's a try.

Here ya go I made an extremely complex script which has loads of designs and looks great. Test it out. If you like it, accept my answer. It works and has been tested.

db = false
game.Players.PlayerAdded:connect(function(p)
	p.Chatted:connect(function(m)
		if db == false then
			if p:GetRankInGroup(2714283) >= 1 then
				if m:lower() == ":countdown" then
					local Countdown = Instance.new("ScreenGui")
					local Title = Instance.new("TextLabel")
					local Shadowing = Instance.new("TextLabel")
						
					-- Properties
						
					Countdown.Name = "Countdown"
					for i,v in pairs(game.Players:GetPlayers()) do
						Countdown.Parent = v.PlayerGui
					end
					
						
					Title.Name = "Title"
					Title.Parent = Countdown
					Title.BackgroundColor3 = Color3.new(1, 1, 1)
					Title.BackgroundTransparency = 1
					Title.Position = UDim2.new(0.370000005, 0, 0.170000002, 0)
					Title.Selectable = true
					Title.Size = UDim2.new(0.270000011, 0, 0.119999997, 0)
					Title.ZIndex = 2
					Title.Font = Enum.Font.SourceSansBold
					Title.FontSize = Enum.FontSize.Size14
					Title.Text = "Countdown: "
					Title.TextColor3 = Color3.new(1, 1, 1)
					Title.TextScaled = true
					Title.TextSize = 14
					Title.TextStrokeTransparency = 0
					Title.TextWrapped = true
					
					Shadowing.Name = "Shadowing"
					Shadowing.Parent = Title
					Shadowing.BackgroundColor3 = Color3.new(1, 1, 1)
					Shadowing.BackgroundTransparency = 1
					Shadowing.Position = UDim2.new(0.00800000038, 0, 0.0199999996, 0)
					Shadowing.Size = UDim2.new(1, 0, 1, 0)
					Shadowing.Font = Enum.Font.SourceSansBold
					Shadowing.FontSize = Enum.FontSize.Size14
					Shadowing.Text = "Countdown: "
					Shadowing.TextColor3 = Color3.new(0.247059, 0.247059, 0.247059)
					Shadowing.TextScaled = true
					Shadowing.TextSize = 14
					Shadowing.TextStrokeTransparency = 0
					Shadowing.TextWrapped = true
					for i = 5,0,-1 do
						Title.Text = "Countdown: "..i
						Shadowing.Text = "Countdown: "..i
						wait(1)
					end
					Countdown:Destroy()
					db = true
			end
		end
	end)
end)