How to decrypt / break enigma-encrypted ciphertext with given configuraton? I'm new here--seriously I don't know anything, but my close friend sending me a code and I must solve it. 

The code uses Rotor III, V, VIII;  starting point ABC; reflector BB; and pair OA LU. 

Can someone give me an example and its procedure about solving a question/code using those rules? 

Thank you.
If you know the configuration of the machine you can easily decrypt the message. All you need is an enigma machine, I found one of several emulators online: Enigma emulator.