Understanding the Enigma Machine: A Simple Explanation

The code breaker's at Bletchley park had Enigma machines that has been captured and smuggled out from the enemy.
So they knew how each rotor was wired. But without the code book they did not know the rotor configuration and settings for that Day..!!
So Alan Turing's Machine would have to backward calculate the message to reveal the daily settings. then they would be able to de-code all messages up to the stroke of midnight that day. As in the film the imitation game if you had a word from the message like Hitler then you could narrow down the rotor positions enough for the Turing machine to reveal the Daily settings and hopefully have enough hours left in the day to de-code vital intelligence.
As in the film it was imperative to keep it secret that they had found a way to break the code. As if the Germans suspected they would have had new rotors manufactured with different cross wiring and the Turing machine would be rendered useless until new rotors had been acquired and the Turing machine rotors re-Configured. This may never have been possible and the war could have been prolonged, I have explained the machine in the simplest terms so it is easy to understand the basics of the 3 rotor machine. But there was 6 rotor machines with an added plug board on the front to mix it up even more. These machines were used by the navy mostly for extra security.