When the suit is filed, you will receive summary process summons and a copy of your landlord's complaint. There will be a "return date" on the summons. You must then go to the court clerk's office (the summons will tell you where to go) to file your "appearance" no later than 2 days after the return date on the summons. After you complete your appearance (a relatively simple form), you must then file your "answer" to the eviction suit. The court clerk will provide you with this form. Once you have filed your answer you must immediately mail a copy of it to your landlord or you will automatically lose the case. After you and your landlord have filed all the necessary papers, the court will schedule a hearing for both of you to show up and argue your sides.
At some point along the way, you may decide it best to seek the advice of an experienced Connecticut evictions lawyer who will make sure you are following all the procedures properly, help you defend against your eviction, and advise you as to any rights you may have with in connection with the notice you received and the eviction action itself.