They didn't as computers that could do cryptanalysis did not exist when Bletchley Park had to figure out ways to break the Enigma cypher.

What they did was build a custom semi-programmable electromechanical machine called a Bombe with dozens of sets of Enigma rotors in different combinations running together. By having the machine check automatically rules that had been developed by manual analysis of Enigma messages, it was possible to find initial wheel settings, etc. very rapidly on the Bombe and use them to setup a British machine that worked like the Enigma to decrypt that message.

Cryptanalysis

Cryptanalysis

Code-breaking, or solving cryptograms

The use of the word enigma is apparently an enigma to you! Delicious irony!