In order to select a key, just type it on your keyboard. In this case, we will disable the Pg Dn (Page Down) key. You have the option to restrict the operation of any key you like from here ...

They usually help to combine keys or enable an elevated extra key marked on the keyboard. If you have seen extra keys marked on a key, i.e., in the image you can see there is a dot, hyphen ...

This keyboard has served me well ... The only feedback you get is from bottoming out, or pushing the keys down as far as they can go. It may not seem that stressful to your fingertips, but ...