How to import from china

I am a US freight broker and I have been contacted by a NVOCC about arranging US tranport of containers inbound from China. As a broker can I do this or must they use a freight forwarder. I can arrange the transport, I have the companies.. but is it legal. I do not understand the process for importing. Can anyone explain the process for me. I would really like to do business with this customer.. but I need to know if I can.