[Haskell-beginners] Understanding "Signals, Not Generators"

Hey I am currently reading Signals, Not Generators". I am on page 10 where the phantom type era is introduced. I have trouble understanding because I do not understand how the system is to be used. Let us assume I have a signal and an action to print the output: signal :: DSignal era Int action :: Int -> Io () action = putStrLn . show Now, I consume the signal: reactive = consume signal action => reactive :: Reactive era (IO ()) And make an io action: toIO reactive :: IO () My question is: what does this io action do? Thanks!