I already have one year residence permit as a student, what other things I'm required to certify.

Hey, Johnpaul, even if you have mainland PRC residence permit, you need to apply for another visa to enter HK because it requires separate entry permits to PRC and HK.
You need to prepare those documents including the application form with a recently-taken passport-style color photo, your passport and copy of its data page, financial support proof, travel itinerary to HK as well as your transportation arrangement and your mainland PRC residence permit. Afterwards, post your application to HK immigration department or submit it to the Office of HK Special Administrative Region in Beijing.