The function "keypad’’ is defined if you look at the bottom of the code, right click on the Keypad Purple Block and click expand block. You can then see how I defined it.
As for the imperial = 1 or 0, it just converts your metric height into imperial height by the touch of the button. For example if you were to type 186 into the keypad and then click the imperial it will read 6.09 feet.
I really enjoy your hard work and perseverance keep it up. I speak from experience when I say coding is hard and takes a lot of practice. Do not worry you will get used to it eventually