I want to find my ancestral surname - Can I get help in Gangnam?

Hello, I have a question about family names, so I am writing this post. My Korean is not very good, but before my father passed away, he told us the family names of our children's generation. We gave our children English names, but also created Korean names using Chinese characters. Recently, my eldest child has been curious about his Korean name and the family names of the next generation. Is there a place in Gangnam where I can find information related to this? It would be even better if there are materials in English. Although the children are still young, I would like to know out of personal curiosity. Thank you to anyone who can help.