When you appeal a decision, you get to have your case heard again. This is called a hearing. You have the right to be there at the hearing and speak for yourself. If you want, you can also have someone else speak for you. Anyone else who had the right to be at the first review can also come to this hearing and speak.
The appeal is like starting over. The court will look at your case again from the beginning. If there are questions about what really happened, the court might look at new evidence. But there are special rules about how they can do this, which are explained in another part of the law.