How does HOA transition to self-management?

I live in a townhouse with 13 neighbors. Our landscaping, water, garbage and incidentals are handled by a property management company who divides up the bills, collects the money and pays them monthly. They only charge $140 a month. They are closing and we are too small for another company to take over. With that said, we may need to do this ourselves but need to ensure it’s done legally. Any thoughts or tips on how to get this started?  Washington State.