Financial Documents

When do I send the “Financial Statement of personal or family support” for international student. There is no deadline but it states " Along with your application for admission, you must submit the financial statement of Personal or Family Support, accompanied by documentation of available funds"

I have an A-1 Visa which is a diplomatic visa and I have the right to work as much as I want. I can’t afford the school if I don’t receive merit (I know it’s competitive). Does anyone know what this is?