I got my HRP a few months ago. I went to a few CTS branches to see how busy they were (Central, Mong Kok, Kowloon Bay & Tuen Mun) I chose and booked an appointment online for Tuen Mun as it was the smallest Branch and least busiest. I can't read, write or speak Chinese so I had to bring a friend along to fill in the 2 forms for me (HRP Application and Declaration for foreign born) and talk to the CTS Rep.
I brought along my HKID ***AON (Chinese transliterated name added before I applied for HKSAR Passport) Expired Foreign Passport used to apply for HKID (The CTS Rep photocopied the first time I entered HK and main page), Most recent Foreign Passport (main page photocopied), HKSAR Passport (main page photocopied). I had to write down my Dad's HKID number and contact details and sign my name in Chinese. I was in and out in less than 45 minutes. My friend picked up the card 14 days later after being contacted by phone using my HKSAR Passport and Application receipt.