You don't know anything, which means you don't have the corresponding professional qualifications. According to the regulations, you can't sign. It is precisely because you are not qualified to sign, even if you sign, you will not bear direct legal responsibility, at most, joint and several liability. Many people in the industry sign on behalf of others. If you sign it yourself, it's probably not an important picture. Just sign your name and you'll be fine. If you have a certificate for you to sign, then you need to worry.