Help~

Okay, newbie here. Actually, more like braindead newbie. I'm doing this assignment and it's driving me up a wall, so I figured I'd ask to see if anyone had any suggestions.

I'm making a GUI of Sudoku, and the GUI shows up fine and all, but what's driving me in circles is putting the back end code to the GUI. And adding ActionListeners to the buttons and....I'm a mess. So, if someone could kindly suggest (link, in comment, whatever) the best way to attach code to a GUI constructor, I would love you forever and eeeeever