Cleaning the outside of upstairs windows with the slidey hinge- how to open them wide?

[Miljah]

There is a method of releasing something on each hinge so you can slide the hinges, top and bottom, across to be able to get to the outside of the window to clean it.

Looking for a YouTube video but don't know the search terms to use!

TIA

With mine, I have two 'gold knobs' on the frame next to the window locks - slide them towards each other then the window should be free to pull towards you and lie flat.