How do we get to the next scene from the opening scene?

Question

I know I should've listened during class. There is a line of code that is never used:

NextWindowController nextController = loader.getController();

Comments

Does the answer to Danielle's question also answer yours?

http://lovelace.augustana.edu/q2a/index.php/190/can-someone-explain-this-code-to-me

(If not, perhaps edit your question to make it more clear what you want to have explained...)