Korean language schools are where most students learn Korean. Some universities in Hong Kong, like HKU Space and CUSCS offer Korean courses. They require students to take the full-time and part-time courses and assess them using assignments and exams (not Topik). The Hong Kong Federation of Trade Unions teaches Korean courses as well. If you want to be tutored 1-on-1, you can look for private tutors. They are flexible in adjusting teaching contents and materials to cater your needs and level of knowledge. Learning Korean online might not be the best choice for beginners as they need more guidance when they aren't familiar with the gramatical and voaculary fundamentals.