All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
You are not required to inform people if they ask you what you have no knowledge of. In fact, it is not permissible for you to say what you do not know. Your fear of telling them what you have not understood of the rulings is in its place, and it is not a matter of concealing knowledge. There is nothing wrong with you asking them to look for someone of knowledge who can answer their questions, or they search in a way that suits their situation for someone who will answer their questions and illuminate their path.
Allah knows best.