You should arrange, at your own cost, accident and sickness insurance for the duration of your studies in Hong Kong. The coverage should include provisions for emergency evacuation/rescuer's expenses and repatriation. If you plan to travel outside Hong Kong, you should make sure that your insurance policy covers those destinations as well. You may also be included in your health insurance policies. You should check with your parents about the coverage before coming to Hong Kong.
If you would like to apply for HKBU insurance, please check the details by downloading the form here. For your information, the insurance coverage does not apply to personal travel in and away from Hong Kong. Thus, please make sure you have adequate insurance coverage when travelling in and outside Hong Kong during personal time if you are insured by HKBU insurance.