i am pakistani study in Nanjing, how to get a Hongkong visa without sponsor in Hong Kong?

hi i am from pakistan an i am a student in nanjing ,china.i have a flight to karachi from hongkong,but i dont have visa.may i know how to apply and the big question for me is about sponsor i dont have any sponsor in hk,so what should i do?i have filled my application form with my flight tickets and other required documents.can u help me out about my question to sponsor and how and where to send from nanjing?