You have to show that you have the necessary facts to show that you are aware that the other party is either in the military as defined under the Servicemembers Civil Relief Act or that they are not in the military. If you are unsure whether that is the case or not, you can put that down and file certain actions to determine whether or not they are in the military or not. The courts in many circumstances need that Military Affidavit to process your paperwork.
