Hi Beefy.
The window is left wet after agitating the dirt with the brush which has water flowing through jets or sprays. They are then rinsed normanlly by lifting the brush a few inches away from the window andf rinsing from the top to the bottom. As for corners and sills they get cleaned. I just swipe the brush across them at the bottom.
I know it all sounds foreign abnd strange to trad window cleaners like I was a few short months ago but it does wrk very well indeed. If done properly like with any other tool.
Hope this helps
Andrew