If you have made it past the interview stage and are recommended for selection, that's terrific!
The recruiter will contact you by phone to explain what to expect next. A contract with CERN is subject to a satisfactory medical examination and verification of your diplomas, and in the initial correspondence you will receive, we will guide and advise you on getting all this done.
You will then receive a job offer by email within two weeks of the board, detailing the financial terms of employment.
This will then be followed, a few weeks later, by the formal contract which you will receive both by email with a host of useful information for your arrival at CERN, and by snail mail as well for you to sign and return.
If you didn't get recommended for selection, don't be disheartened and keep applying!