Is there a problem with me using enabled, or did I just write the script wrong?

Edit: You would use GetDescendants as GetChildren only returns direct children

GetChildren returns an array, not a value, you would have to use pairs instead to go through each value.

However, you can just put the script inside the smoke.

local smoke = script.Parent

while true do
	wait(0.01) -- Don't touch
	smoke.Enabled = true
	wait(5) -- How long you want the smoke to stay on
	smoke.Enabled = false
	wait(12) -- How long you want the smoke to stay off then go back on
end

Using GetDescendants

local smoke

repeat wait(1)
	for i,v in pairs(workspace:GetDescendants())do
		if v.Name == "Smoke" and v:IsA("Smoke") then
			smoke = v
			break
		end
	end
until smoke

while true do
	wait(0.01) -- Don't touch
	smoke.Enabled = true
	wait(5) -- How long you want the smoke to stay on
	smoke.Enabled = false
	wait(12) -- How long you want the smoke to stay off then go back on
end