How to Register Cubase LE software !!!!

Hi to all forum mates,

I have purchased an Alesis Audio (UK)Interface included cd of Cubase LE Music Recording software.Before starting the
recording session asking for registering it with the steinberg.Please tell how to do that and also tell after registering will the software continue to work or stop(which i am afraid) after a month as indicating before the recording session.

Love to all forum mates and blessings!