Looking for advice for creating agency

I have access to lots of low price freelancers in different majors and skills. How Can I use this potential to form an agency or earn someway?

I am looking for practical advice from those who went through this path. Otherwise, chatgpt can give generic guidelines too.
Eg. Do I have to be skilled in that niche to create agency around it? What steps should I take from gathering freelancers to acquiring clients. The most cost effective method? Should I sign up in freelance platforms or find other ways to attract clients?

focus on client acquisition / distribution rather than product.

Product is also important but its secondary in that hierarchy