According to the United States Courts, an appeal is when a higher court reviews the decision of a lower court. In a civil case, either side may bring an appeal. That just means you or the other party may appeal the case. In a criminal case, this is different as only the defendant may appeal.
There are different levels of appeals. Any appeal, though, is rooted in the legal arguments of the first case. You present your appeal in a legal brief to the appeals court. The appeals court has a panel of judges that will look over the facts of your case. You have to prove why the first court was incorrect in its ruling or show there was an error made that affected the outcome of the case.
The appeals court may uphold the lower court’s ruling, which means it agrees with the original verdict. It may also disagree with the original verdict and send the case back to the lower court where you will go through a trial again. This information is for education and is not legal advice.