How am I suppose to apply for hong kong tourist visa for 10 day???

First, prepare the relevant documents: travel itinerary, copy of passport, the application form, a passport-style photo, financial support proof, flight tickets and hotel booking record.
Next, submit the application to China embassy. If you make the application for the first time, you need to post it to HK immigration department directly.
Address: Receipt and Despatch Sub-unit
HK Immigration Department
2/F, Immigration Tower
7 Gloucester Road
Wan Chai, HK