This one is simple enough to describe in a paragraph, which is why the recording is short.
Find a window. Sit where you can see out of it. Set ten minutes and then stop looking at the time. Listen to whatever is going on outside — traffic, weather, birds, someone's radio — and when you notice you have gone back inside your own head, which you will, come back out to the noise. That is the entire practice.
It is not meditation and it is not meant to calm you down, though sometimes it does. It is a way of remembering that the world carries on having weather and pigeons in it while you are in the middle of something difficult, and that this is a comfort rather than an insult.
Do it on the days it seems pointless. Those are the days it does the most.