Of course you need a defense. Equally important are the evidence materials from the procuratorate and the law (if you give them the materials of the defenders, they will give them to you on their own initiative. You can have it if you don't give it. Generally, the evidence is directly cross-examined according to the number of the procuratorate-because the prosecutor will follow his own number, and the lawyer will generally not use other numbers, otherwise everything will be chaotic.
That's all. When necessary, there are special letters of introduction for applying for witnesses to appear in court and reappraisal.