Hi pcoronaf,

It's the fourth button from the left\second from the right.

Press it once and an option will pop up in the bottom right and you will see 4 icons and it is the second one which shows a monitor and a small box inside it.

You then have to press the button under that icon (Second button from left) and it will change the position of the box on your screen.

you will have to do this 4-5 times before it will cycle around all positions and back around to the screen being normal.

Hope this works for you.