This is an amazing upgrade to the traditional slate or as we say in Australia hand frame.
So rather than sticking in a bit of paper, writing in Braille, and then having to take the paper out, read what you have Brailled, and then stick it back in again to continue Brailling, you just Braille or write on once side and the pins pop out on the other reading side, for you to just read what you have Brailled.
You can push any pin in with your finger tip to clear pins within a cell or use the buttons at the top and bottom to clear every 5 cells going across: eg first left top and bottom do lines 1 to 4 up to firth cell etc or top left button by itself does lines 1 to 2, and bottom right hand side button does lines3 to 4 etc, then going across to buttons 2, 3, and 4 for top and bottom.
Do not use the stylus to push in the pins on the reading side as you'll damage the pins.
It'll make more sense when you listen to the demo.