In this work, you start by painting a window with a very thin paintbrush. I used black. Just draw the basic lines of the window.

with a wash apply the ink to paint the wall but leave some whites in your paper.

Start doing dots and dashes that represent the flowers of the window

splash the ink of your paintbrush in the area of the flowers. you must use many colours

apply some washes of black to do better the window and clean some spots you don't want

This is the final result dry and without the scotch