first the code will not work, first you’re setting Rotation to true, true is a boolean and Rotation requires Vector3. Second you’re parenting the script to a rotation curve key and at the same time checking if that rotation curve key is = 15. The the last part just isn’t a thing, speed is not a valid member of Rotation.
So let’s make a working one and understand what each thing does.
--First lets make a loop that won't yield (stop the rest of the script from running)
game:GetService("RunService").Stepped:Connect(function() --runs each step of the server
local part = script.Parent
part.Orientation += Vector3.new(0,1,0) --Add 1 degree on the Y rotation (+=) adds to the current number (-=) does the opposite (*=) multiply by current value (=) set current value to a completely new value (==) returns true or false depending if the thing before the = is the same as the one after
end)
that should work