What materials do defense lawyers need to prepare in criminal proceedings?

If a family member entrusts a lawyer to defend, the lawyer shall go through the entrustment procedures, including the interview letter issued by the law firm, the lawyer's practice certificate and the power of attorney signed by the close relatives of the person involved. The lawyer shall meet during the handling of the case, communicate with the case-handling organ and submit a legal opinion, and submit a defense at the court stage. That's about it.