In what jobs do people often have to work nights?
nurses, doctors, factory workers, and restaurant and hotel staff
What do you do to apply for and get a job?
To apply for a job you need to send a CV or application form and covering letter, have an interview and accept if they offer you the job
Say three different times when you might have to sign a contract.
You might have to sign a contract when you get a job, buy a mobile phone, buy / rent a house or flat, etc.