Look on your keyboard.
I have the regular English Qwerty keys on the main (these are the ones with the letters).
On the right of that - at bottom are the directional arrows (up, down, right, left).
On my keyboard, the page up/down is above those arrows and right of the regular letter keys.
In some keyboards, the page up/down (page scroll) are on the top line.
Take a look at the picture on
this page. It is exactly like mine with the page scroll above the arrows.