How does one go about taking this script: --In a server script with fe it works
local getlights = game.Workspace.Lights:GetChildren()
game:GetService("RunService").RenderStepped:connect(function()
for i = 1, #getlights do
if getlights[i].PointLight.Enabled == true then
getlights[i].PointLight.Enabled = false
print("all off")
else
getlights[i].PointLight.Enabled = true
print("all on")
end
end
end)
and put it in a local script with fe, So it works in play mode.

4 comments
Problem is [RenderStepped] can not be ran from a Server Side Script through a server, it will however work in LocalScripts. Btw, kudos for using the not keyword to change the PointLight Enabled variable.
RunService can be used in a server script. RenderStepped can't.
Sorry, my bad.
Don't forget; There is also the 'HeartBeat' event of 'RunService' that fires 1/60th of a Second as well (at least, that's how it fire(d) for me). :)