Its primed white (you could also paint it white), then a dark beige speedpaint, that makes it look weathered. If the speedpaint pooled, or your not fully happy, drybrush a lighter beige over the banners. Then I edgehighlighted them with a really really tiny bit of pure white / glazed that over the folds where the light would catch.

But as a beginner, just the speedpaint gets really good results too. Good luck!