Physics Blockly Blocks acting at the same time

I have a question. Do you use the function " keypad " on the code number 1? But can you use the " keypad " function without defining the function separately?

And if you look at number two, is it true that " Imperials? = 1 " means " If you typed the key as Imperial? "

And if it is " 0, " does it mean it is not? (i.e. " Metric ")

I am not good at coding. So I ask for your help. I think you’re the expert.
I am learning hard. But it’s too difficult.