Need help understanding how to initalize a particular example

Also yes, I am not a complete idiot like some people seem to think, and I do in fact know conceptually/in theory that you have to use a procedure after you declare it, or that you need to initailize a variable before using it or it’s undefined otherwise, cause I know that’s how programming in general works,

It’s just the details/implementation is where I get stuck, like my question above shows.