1. Contact the child's armed forces or military organizations, and they may provide information about the child's army.
2. Find your child's comrades-in-arms or family members through social media, phone books and other channels and ask for relevant information.
If you know which school your child goes to, you can ask the school for contact information and address.
4. If the child has a mobile phone number or other contact information, you can ask directly by text message or telephone.
It should be noted that due to confidentiality regulations, some information may not be disclosed publicly. It is recommended that you consult a professional for help.