How did Medieval East Asia and South Asia design their flags?

Hello!

For some context, I am currently writing a story with setting inspired off a blend of medieval south asian and east asian societies.

I wanted to ask how states/dynasties/kingdoms from East and South Asia would use flags (or whatever medium of establishing soverignty like banners), how these flags were designed proprtionally, what was on them, and how do they compare to Medieval Europe's?

Any response would be greatly appreciated, thank you all so much!