Your landlord must prove to the Judge that the facts in the Complaint are true. For example, you have not paid your rent, you were given proper notice, or you violated your lease/house rules. Your landlord will also have to prove that you are still living in the unit.
If the Judge decides that your landlord has not proven the facts in the Complaint, you then get a chance to tell the Judge your side of the story. Once the Judge hears from you and your landlord, he/she will decide which one of you he/she agrees with.